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Hypoxanthine, also known as purine-6-ol or Hyp, belongs to the class of organic compounds known as purines. Purines are a bicyclic aromatic compound made up of a pyrimidine ring fused to an imidazole ring. Hypoxanthine is also classified as an oxopurine, Hypoxanthine is a naturally occurring purine derivative and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the nucleotide salvage pathway. Hypoxanthine exists in all living species, ranging from bacteria to plants to humans. Hypoxanthine has been detected, but not quantified in, several different foods, such as radish (var.), mountain yams, welsh onions, greenthread tea, and common beets. Hypoxanthine is occasionally found as a constituent of nucleic acids, where it is present in the anticodon of tRNA in the form of its nucleoside inosine. Biologically, hypoxanthine can be formed a number of ways. For instance, it is one of the products of the action of xanthine oxidase on xanthine. However, more frequently xanthine is formed from oxidation of hypoxanthine by xanthine oxidoreductase. The enzyme hypoxanthine-guanine phosphoribosyltransferase converts hypoxanthine into IMP in the nucleotide salvage pathway. Hypoxanthine is also a spontaneous deamination product of adenine. Under normal circumstances hypoxanthine is readily converted to uric acid. In this process, hypoxanthine is first oxidized to xanthine, which is further oxidized to uric acid by xanthine oxidase. Molecular oxygen, the oxidant in both reactions, is reduced to H2O2 and other reactive oxygen species. In humans, uric acid is the final product of purine degradation and is excreted in the urine. Within humans, hypoxanthine participates in a number of other enzymatic reactions. In particular, hypoxanthine and ribose 1-phosphate can be biosynthesized from inosine through its interaction with the enzyme purine nucleoside phosphorylase. Hypoxanthine is also involved in the metabolic disorder called the purine nucleoside phosphorylase deficiency. Purine nucleoside phosphorylase (PNP) deficiency is a disorder of the immune system (primary immunodeficiency) characterized by recurrent infections, neurologic symptoms, and autoimmune disorders. PNP deficiency causes a shortage of white blood cells, called T-cells, that help fight infection. Affected individuals develop neurologic symptoms, such as stiff or rigid muscles (spasticity), uncoordinated movements (ataxia), developmental delay, and intellectual disability. PNP deficiency is associated with an increased risk to develop autoimmune disorders, such as autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura (ITP), autoimmune neutropenia, thyroiditis, and lupus.

Xanthine, also known as 2,6-dioxopurine, belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety. Xanthine is also classified as an oxopurine. An oxopurine in which the purine ring is substituted by oxo groups at positions 2 and 6 and N-9 is protonated. Xanthine exists in all living species, ranging from bacteria to plants to humans. In plants, several stimulants can be derived from xanthine, including caffeine, theophylline, and theobromine. Derivatives of xanthine (known collectively as xanthines) are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, notably in the treatment of asthma or influenza symptoms. Within humans, xanthine participates in a number of enzymatic reactions. In particular, xanthine can be biosynthesized from guanine; which is mediated by the enzyme guanine deaminase. In addition, xanthine and ribose 1-phosphate can be biosynthesized from xanthosine through the action of the enzyme purine nucleoside phosphorylase. In humans and other primates, xanthine can be converted to uric acid by the action of the xanthine oxidase enzyme. People with rare genetic disorders, specifically xanthinuria and Lesch–Nyhan syndrome, lack sufficient xanthine oxidase and cannot convert xanthine to uric acid. Individuals with xanthinuria have unusually high concentrations of xanthine in their blood and urine, which can lead to health problems such as renal failure and xanthine kidney stones. Individuals with Lesch-Nyhan syndrome have a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). The HGPRT deficiency causes a build-up of uric acid in all body fluids. This results in both high levels of uric acid in the blood and urine, associated with severe gout and kidney problems. Neurological signs include poor muscle control and moderate intellectual disability.

Oxipurinol is a xanthine oxidase inhibitor. Oxipurinol is potentially used for treatment of congestive heart failure. PMID: 15139781.

An alpha-amino acid that is phenylalanine bearing a hydroxy substituent at position 4 on the phenyl ring." []

Tyrosine (Tyr) or L-tyrosine is an alpha-amino acid. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Amino acids are organic compounds that contain amino (–NH2) and carboxyl (–COOH) functional groups, along with a side chain (R group) specific to each amino acid. L-tyrosine is one of 20 proteinogenic amino acids, i.e., the amino acids used in the biosynthesis of proteins. Tyrosine is found in all organisms ranging from bacteria to plants to animals. It is classified as a non-polar, uncharged (at physiological pH) aromatic amino acid. Tyrosine is a non-essential amino acid, meaning the body can synthesize it – usually from phenylalanine. The conversion of phenylalanine to tyrosine is catalyzed by the enzyme phenylalanine hydroxylase, a monooxygenase. This enzyme catalyzes the reaction causing the addition of a hydroxyl group to the end of the 6-carbon aromatic ring of phenylalanine, such that it becomes tyrosine. Tyrosine is found in many high-protein food products such as chicken, turkey, fish, milk, yogurt, cottage cheese, cheese, peanuts, almonds, pumpkin seeds, sesame seeds, soy products, lima beans, avocados and bananas. Tyrosine is one of the few amino acids that readily passes the blood-brain barrier. Once in the brain, it is a precursor for the neurotransmitters dopamine, norepinephrine and epinephrine, better known as adrenalin. These neurotransmitters are an important part of the body's sympathetic nervous system, and their concentrations in the body and brain are directly dependent upon dietary tyrosine. Tyrosine is not found in large concentrations throughout the body, probably because it is rapidly metabolized. Folic acid, copper and vitamin C are cofactor nutrients of these reactions. Tyrosine is also the precursor for hormones, including thyroid hormones (diiodotyrosine), catecholestrogens and the major human pigment, melanin. Tyrosine is an important amino acid in many proteins, peptides and even enkephalins, the body's natural pain reliever. Valine and other branched amino acids, and possibly tryptophan and phenylalanine may reduce tyrosine absorption. A number of genetic errors of tyrosine metabolism have been identified, such as hawkinsinuria and tyrosinemia I. The most common feature of these diseases is the increased amount of tyrosine in the blood, which is marked by decreased motor activity, lethargy and poor feeding. Infection and intellectual deficits may occur. Vitamin C supplements can help reverse these disease symptoms. Some adults also develop elevated tyrosine in their blood. This typically indicates a need for more vitamin C. More tyrosine is needed under stress, and tyrosine supplements prevent the stress-induced depletion of norepinephrine and can help aleviate biochemical depression. However, tyrosine may not be good for treating psychosis. Many antipsychotic medications apparently function by inhibiting tyrosine metabolism. L-Dopa, which is directly used in Parkinson's, is made from tyrosine. Tyrosine, the nutrient, can be used as an adjunct in the treatment of Parkinson's. Peripheral metabolism of tyrosine necessitates large doses of tyrosine, however, compared to L-Dopa (http://www.dcnutrition.com). In addition to its role as a precursor for neurotransmitters, tyrosine plays an important role for the function of many proteins. Within many proteins or enzymes, certain tyrosine residues can be tagged (at the hydroxyl group) with a phosphate group (phosphorylated) by specialized protein kinases. In its phosphorylated form, tyrosine is called phosphotyrosine. Tyrosine phosphorylation is considered to be one of the key steps in signal transduction and regulation of enzymatic activity. Tyrosine (or its precursor phenylalanine) is also needed to synthesize the benzoquinone structure which forms part of coenzyme Q10.

A 2-hydroxy monocarboxylic acid that is propanoic acid in which one of the alpha-hydrogens is replaced by a hydroxy group." []

Creatine, is a naturally occurring non-protein compound. It belongs to the class of organic compounds known as alpha amino acids and derivatives. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon), or a derivative thereof. Creatine is found in all vertebrates where it facilitates recycling of adenosine triphosphate (ATP). Its primary metabolic role is to combine with a phosphoryl group, via the enzyme creatine kinase, to generate phosphocreatine, which is used to regenerate ATP. Most of the human body's total creatine and phosphocreatine stores are found in skeletal muscle (95%), while the remainder is distributed in the blood, brain, testes, and other tissues. Creatine is not an essential nutrient as it is naturally produced in the human body from the amino acids glycine and arginine, with an additional requirement for methionine to catalyze the transformation of guanidinoacetate to creatine. In the first step of its biosynthesis glycine and arginine are combined by the enzyme arginine:glycine amidinotransferase (AGAT) to form guanidinoacetate, which is then methylated by guanidinoacetate N-methyltransferase (GAMT), using S-adenosyl methionine as the methyl donor. Creatine can also be obtained through the diet at a rate of about 1 gram per day from an omnivorous diet. A cyclic form of creatine, called creatinine, exists in equilibrium with its tautomer and with creatine. Clinically, there are three distinct disorders of creatine metabolism. Deficiencies in the two synthesis enzymes (AGAT and GAMT) can cause L-arginine:glycine amidinotransferase deficiency (caused by variants in AGAT) and guanidinoacetate methyltransferase deficiency (caused by variants in GAMT). Both disorders are inherited in an autosomal recessive manner. A third defect, creatine transporter defect, is caused by mutations in SLC6A8 and inherited in a X-linked manner. Creatine is widely used as a supplement by athletes. Its use can increase maximum power and performance in high-intensity anaerobic repetitive work (periods of work and rest) by 5 to 15% (PMID: 24688272). Creatine has no significant effect on aerobic endurance, although it will increase power during short sessions of high-intensity aerobic exercise (PMID: 9662683).

The D-enantiomer of 5-oxoproline." []

Succinic acid (succinate) is a dicarboxylic acid. It is an important component of the citric acid or TCA cycle and is capable of donating electrons to the electron transfer chain. Succinate is found in all living organisms ranging from bacteria to plants to mammals. In eukaryotes, succinate is generated in the mitochondria via the tricarboxylic acid cycle (TCA). Succinate can readily be imported into the mitochondrial matrix by the n-butylmalonate- (or phenylsuccinate-) sensitive dicarboxylate carrier in exchange with inorganic phosphate or another organic acid, e. g. malate (PMID 16143825). Succinate can exit the mitochondrial matrix and function in the cytoplasm as well as the extracellular space. Succinate has multiple biological roles including roles as a metabolic intermediate and roles as a cell signalling molecule. Succinate can alter gene expression patterns, thereby modulating the epigenetic landscape or it can exhibit hormone-like signaling functions (PMID: 26971832). As such, succinate links cellular metabolism, especially ATP formation, to the regulation of cellular function. Succinate can be broken down or metabolized into fumarate by the enzyme succinate dehydrogenase (SDH), which is part of the electron transport chain involved in making ATP. Dysregulation of succinate synthesis, and therefore ATP synthesis, can happen in a number of genetic mitochondrial diseases, such as Leigh syndrome, and Melas syndrome. Succinate has been found to be associated with D-2-hydroxyglutaric aciduria, which is an inborn error of metabolism. Succinic acid has recently been identified as an oncometabolite or an endogenous, cancer causing metabolite. High levels of this organic acid can be found in tumors or biofluids surrounding tumors. Its oncogenic action appears to due to its ability to inhibit prolyl hydroxylase-containing enzymes. In many tumours, oxygen availability becomes limited (hypoxia) very quickly due to rapid cell proliferation and limited blood vessel growth. The major regulator of the response to hypoxia is the HIF transcription factor (HIF-alpha). Under normal oxygen levels, protein levels of HIF-alpha are very low due to constant degradation, mediated by a series of post-translational modification events catalyzed by the prolyl hydroxylase domain-containing enzymes PHD1, 2 and 3, (also known as EglN2, 1 and 3) that hydroxylate HIF-alpha and lead to its degradation. All three of the PHD enzymes are inhibited by succinate. In humans, urinary succinic acid is produced by Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Enterobacter, Acinetobacter, Proteus mirabilis, Citrobacter frundii, Enterococcus faecalis (PMID: 22292465). Succinic acid is also found in Actinobacillus, Anaerobiospirillum, Mannheimia, Corynebacterium and Basfia (PMID: 22292465; PMID: 18191255; PMID: 26360870).

2-Amino-3-methyl-1-butanol is an amino alcohol.

o-Tyrosine is a normal human metabolite. Its presence is possible due to the hydroxylation of l-phenylalanine by hydroxyl radical (*OH), and is proposed as an hydroxy radical biomarker of oxidative damage to proteins. o-Tyrosine might also be included in the diet and absorbed. It has been associated with disease such as Kwashiorkor, a severe form of protein-energy malnutrition. However, many publications mention that the results are inconclusive, and o-tyrosine is not selectively altered by antioxidant intervention, exercise training or age. (PMID:14670743, 10969271, 9887186).

Methoxyacetic acid belongs to the family of Carboxylic Acids. These are compounds containing a carboxylic acid group with the formula -C(=O)OH.

Meta-Tyrosine, or M-Tyrosine for short, is a natural weed suppressant found in certain Fine fescue grass. M-tyrosine exudes out of the grass plant's roots and is then absorbed by neighbouring weed seedlings. The weed plants will either die or be stunted from the toxic acid.

Glycerophosphorylcholine (GPC) is a choline derivative and one of the two major forms of choline storage (along with phosphocholine) in the cytosol. Glycerophosphorylcholine is also one of the four major organic osmolytes in renal medullary cells, changing their intracellular osmolyte concentration in parallel with extracellular tonicity during cellular osmoadaptation. As an osmolyte, Glycerophosphorylcholine counteracts the effects of urea on enzymes and other macromolecules. Kidneys (especially medullar cells), which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond to hypertonic stress by accumulating the organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents of these osmolytes are achieved by a combination of increased uptake (myo-inositol and betaine) and synthesis (sorbitol, GPC), decreased degradation (GPC) and reduced osmolyte release. GPC is formed in the breakdown of phosphatidylcholine (PtC). This pathway is active in many body tissues, including mammary tissue.

Methylmalonic acid is a malonic acid derivative, which is a vital intermediate in the metabolism of fat and protein. In particular, the coenzyme A-linked form of methylmalonic acid, methylmalonyl-CoA, is converted into succinyl-CoA by methylmalonyl-CoA mutase in a reaction that requires vitamin B12 as a cofactor. In this way, methylmalonic acid enters the Krebs cycle and is thus part of one of the anaplerotic reactions. Abnormalities in methylmalonic acid metabolism lead to methylmalonic aciduria. This inborn error of metabolism is attributed to a block in the enzymatic conversion of methylmalonyl CoA to succinyl CoA. Methylmalonic acid is also found to be associated with other inborn errors of metabolism, including cobalamin deficiency, cobalamin malabsorption, malonyl-CoA decarboxylase deficiency, and transcobalamin II deficiency. When present in sufficiently high levels, methylmalonic acid can act as an acidogen and a metabotoxin. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of methylmalonic acid are associated with at least 5 inborn errors of metabolism, including Malonyl CoA decarboxylase deficiency, Malonic Aciduria, Methylmalonate Semialdehyde Dehydrogenase Deficiency, Methylmalonic Aciduria and Methylmalonic Aciduria Due to Cobalamin-Related Disorders. Methylmalonic acid is an organic acid and abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. In infants with acidosis, the initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, kidney abnormalities, liver damage, seizures, coma, and possibly death. These are also the characteristic symptoms of the untreated IEMs mentioned above. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and seizures.

Taurine is a sulfur amino acid like methionine, cystine, cysteine, and homocysteine. It is a lesser-known amino acid because it is not incorporated into the structural building blocks of protein. Yet taurine is an essential amino acid in pre-term and newborn infants of humans and many other species. Adults can synthesize their own taurine, yet are probably dependent, in part, on dietary taurine. Taurine is abundant in the brain, heart, breast, gallbladder, and kidney and has important roles in health and disease in these organs. Taurine has many diverse biological functions including serving as a neurotransmitter in the brain, a stabilizer of cell membranes, and a facilitator in the transport of ions such as sodium, potassium, calcium, and magnesium. Taurine is highly concentrated in animal and fish protein, which are good sources of dietary taurine. It can be synthesized by the body from cysteine when vitamin B6 is present. Deficiency of taurine occurs in premature infants, neonates fed formula milk, and various disease states. Several inborn errors of taurine metabolism have been described. Perry syndrome is an unusual neuropsychiatric disorder inherited in an autosomal dominant fashion through three generations of a family. Symptoms began late in the fifth decade in 6 affected persons and death occurred after 4 to 6 years. The earliest and most prominent symptom was mental depression that was not responsive to antidepressant drugs or electroconvulsive therapy. Sleep disturbances, exhaustion, and marked weight loss were features. Parkinsonism developed later, and respiratory failure occurred terminally (OMIM: 168605). Hypertaurinuric cardiomyopathy describes congestive cardiomyopathy and markedly elevated urinary taurine levels (about 5 times normal). Other family members had late or holosystolic mitral valve prolapse and elevated urinary taurine values (about 2.5 times normal). In two with mitral valve prolapse, congestive cardiomyopathy eventually developed while the amounts of urinary taurine doubled (OMIM: 145350). Taurine, after GABA, is the second most important inhibitory neurotransmitter in the brain. Its inhibitory effect is one source of taurine's anticonvulsant and antianxiety properties. It also lowers glutamic acid in the brain, and preliminary clinical trials suggest taurine may be useful in some forms of epilepsy. Taurine in the brain is usually associated with zinc or manganese. The amino acids alanine and glutamic acid, as well as pantothenic acid, inhibit taurine metabolism while vitamins A and B6, zinc, and manganese help build taurine. Cysteine and B6 are the nutrients most directly involved in taurine synthesis. Taurine levels have been found to decrease significantly in many depressed patients. One reason that the findings are not entirely clear is that taurine is often elevated in the blood of epileptics who need it. It is often difficult to distinguish compensatory changes in human biochemistry from true metabolic or deficiency disease. Low levels of taurine are found in retinitis pigmentosa. Taurine deficiency in experimental animals produces degeneration of light-sensitive cells. Therapeutic applications of taurine to eye disease are likely to be forthcoming. Taurine has many important metabolic roles. Supplements can stimulate prolactin and insulin release. The parathyroid gland makes a peptide hormone called glutataurine (glutamic acid-taurine), which further demonstrates taurine's role in endocrinology. Taurine increases bilirubin and cholesterol excretion in bile, critical to normal gallbladder function. It seems to inhibit the effect of morphine and potentiates the effects of opiate antagonists. Low plasma taurine levels have been found in a variety of conditions, i.e. depression, hypertension, hypothyroidism, gout, institutionalized patients, infertility, obesity, kidney failure, and others (http://www.dcnutrition.com/AminoAcids/). Moreover, taurine is found to be associated with maple syrup urine disease, which is an inborn error of metabolism.

L-m-tyrosine is a hydroxyphenylalanine that is L-phenylalanine with a substituent hydroxy group at position 3. It has a role as a plant metabolite. It is a hydroxyphenylalanine, a L-phenylalanine derivative, a non-proteinogenic L-alpha-amino acid and a member of phenols. It is a tautomer of a L-m-tyrosine zwitterion.

Urocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).

D-Maltose, also known as maltose, maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an alpha (1→4) bond. Its name comes from malt, combined with the suffix '-ose' which is used in names of sugars. Maltose is a key structural motif of starch. When alpha-amylase breaks down starch, it removes two glucose units at a time, producing maltose. Maltose can be further broken down to glucose by the maltase enzyme, which catalyses the hydrolysis of the glycosidic bond. D-maltose exists in all living species, ranging from bacteria to plants to humans. Within humans, D-maltose participates in a number of enzymatic reactions. In particular, maltose can be converted into glucose; which is mediated by the enzyme maltase-glucoamylase. In addition, maltose can be converted into glucose through its interaction with the enzyme glycogen debranching enzyme. Maltose is found in high concentrations in oriental wheats and in a lower concentrations in sweet potato, grape wines, yellow pond-lilies, sunflowers, and spinach. Maltose is a component of malt, a substance which is obtained in the process of allowing grain to soften in water and germinate. It is also present in highly variable quantities in partially hydrolysed starch products like maltodextrin, corn syrup and acid-thinned starch. Maltose has a sweet taste but is only about 30–60% as sweet as sucrose, depending on the concentration.

A glycosylfructose that is D-fructofuranose attached to a alpha-D-glucopyranosyl unit at position 6 via a glycosidic linkage. It is found in honey and sugarcane." []

An optically active form of tyrosine having D-configuration." []

A hydroxybenzaldehyde that is 4-hydroxybenzaldehyde substituted by methoxy groups at positions 3 and 5. Isolated from Pisonia aculeata and Panax japonicus var. major, it exhibits hypoglycemic activity." []

2,2,6,6-Tetramethyl-4-piperidinone is found in green vegetables. 2,2,6,6-Tetramethyl-4-piperidinone is isolated from Viola odorata (sweet violet

2-Phenylacetamide is an intermediate in phenylalanine metabolism and styrene degradation(KEGG ID C02505). It is the third to last step in the synthesis of phenylacetylglutamine and is converted from phenylalanine via the enzyme phenylalanine 2-monooxygenase [EC:1.13.12.9]. It is then converted to phenylacetate via the enzyme amidase [EC:3.5.1.4].

1,1-Dihydroxypropan-2-one is a natural product found in Homo sapiens, Catharanthus roseus, and other organisms with data available.

3,4-Dihydroxyhydrocinnamic acid, also known as dihydrocaffeic acid (DHCA), is a metabolite product of the hydrogenation of caffeoylquinic acids, occurring in normal human biofluids, with potent antioxidant properties. DHCA has been detected in human plasma following coffee ingestion (PMID: 15607645) and is increased with some dietary sources, such as after ingestion of phenolic constituents of artichoke leaf extract (PMID: 15693705). Polyphenol-rich foods such as vegetables and fruits have been shown to significantly improve platelet function in ex vivo studies in humans (PMID: 16038718). Its antioxidant activity has been tested to reduce ferric iron in the ferric reducing antioxidant power (FRAP) assay, and it has been suggested that its catechol structure conveys the antioxidant effect in plasma and in erythrocytes (PMID: 11768243). 3,4-Dihydroxyhydrocinnamic acid is a microbial metabolite found in Bifidobacterium, Escherichia, Lactobacillus, and Clostridium (PMID: 28393285).

N-Acetyl-L-Aspartic acid (NAA) or N-Acetylaspartic acid, belongs to the class of organic compounds known as N-acyl-alpha amino acids. N-acyl-alpha amino acids are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. N-alpha-Acetyl-L-aspartic acid can also be classified as an alpha amino acid or a derivatized alpha amino acid. Technically, N-Acetyl-L-aspartic acid is a biologically available N-terminal capped form of the proteinogenic alpha amino acid L-aspartic acid. N-acetyl amino acids can be produced either via direct synthesis of specific N-acetyltransferases or via the proteolytic degradation of N-acetylated proteins by specific hydrolases. N-terminal acetylation of proteins is a widespread and highly conserved process in eukaryotes that is involved in protection and stability of proteins (PMID: 16465618). About 85% of all human proteins and 68% of all yeast proteins are acetylated at their N-terminus (PMID: 21750686). Several proteins from prokaryotes and archaea are also modified by N-terminal acetylation. The majority of eukaryotic N-terminal-acetylation reactions occur through N-acetyltransferase enzymes or NAT’s (PMID: 30054468). These enzymes consist of three main oligomeric complexes NatA, NatB, and NatC, which are composed of at least a unique catalytic subunit and one unique ribosomal anchor. The substrate specificities of different NAT enzymes are mainly determined by the identities of the first two N-terminal residues of the target protein. The human NatA complex co-translationally acetylates N-termini that bear a small amino acid (A, S, T, C, and occasionally V and G) (PMID: 30054468). NatA also exists in a monomeric state and can post-translationally acetylate acidic N-termini residues (D-, E-). NatB and NatC acetylate N-terminal methionine with further specificity determined by the identity of the second amino acid. N-acetylated amino acids, such as N-acetylaspartate can be released by an N-acylpeptide hydrolase from peptides generated by proteolytic degradation (PMID: 16465618). In addition to the NAT enzymes and protein-based acetylation, N-acetylation of free aspartic acid can also occur. In particular, N-Acetyl-L-aspartic acid can be synthesized in neurons from the amino acid aspartate and acetyl coenzyme A (acetyl CoA). Specifically, the enzyme known as aspartate N-acetyltransferase (EC 2.3.1.17) catalyzes the transfer of the acetyl group of acetyl CoA to the amino group of aspartate. N-Acetyl-L-aspartic acid is the second most concentrated molecule in the brain after the amino acid glutamate. The various functions served by N-acetylaspartic acid are still under investigation, but the primary proposed functions include (1) acting as a neuronal osmolyte that is involved in fluid balance in the brain, (2) serving as a source of acetate for lipid and myelin synthesis in oligodendrocytes (the glial cells that myelinate neuronal axons), (3) serving as a precursor for the synthesis of the important dipeptide neurotransmitter N-acetylaspartylglutamate (NAAG), and (4) playing a potential role in energy production from the amino acid glutamate in neuronal mitochondria. High neurotransmitter (i.e. N-acetylaspartic acid) levels can lead to abnormal neural signaling, delayed or arrested intellectual development, and difficulties with general motor skills. When present in sufficiently high levels, N-acetylaspartic acid can be a neurotoxin, an acidogen, and a metabotoxin. A neurotoxin is a compound that disrupts or attacks neural tissue. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of N-acetylaspartic acid are associated with Canavan disease. Because N-acetylaspartic acid functions as an organic acid and high levels of organic acids can lead to a condition known as acidosis. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. Infants with acidosis have symptoms that include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, seizures, coma, and possibly death. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and flapping tremors. Many N-acetylamino acids, including N-acetylaspartic acid, are classified as uremic toxins if present in high abundance in the serum or plasma (PMID: 26317986; PMID: 20613759). Uremic toxins are a diverse group of endogenously produced molecules that, if not properly cleared or eliminated by the kidneys, can cause kidney damage, cardiovascular disease and neurological deficits (PMID: 18287557).

The use of tyrosine kinase receptor inhibitors is increasingly becoming a valuable therapeutic alternative in tumors carrying activated tyrosine kinase receptors. GMR beta tyrosine residues are not necessary for activation of the JAK/STAT pathway, or for proliferation, viability, or adhesion signaling in Ba/F3 cells, although tyrosine residues significantly affect the magnitude of the response. (PMID:10372132).

Alanine (Ala), also known as L-alanine is an alpha-amino acid. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Amino acids are organic compounds that contain amino (–NH2) and carboxyl (–COOH) functional groups, along with a side chain (R group) specific to each amino acid. L-alanine is one of 20 proteinogenic amino acids, i.e., the amino acids used in the biosynthesis of proteins. Alanine is found in all organisms ranging from bacteria to plants to animals. It is classified as an aliphatic, non-polar amino acid. In humans, alanine is a non-essential amino acid that can be easily made in the body from either the conversion of pyruvate or the breakdown of the dipeptides carnosine and anserine. Alanine can be also synthesized from branched chain amino acids such as valine, leucine, and isoleucine. Alanine is produced by reductive amination of pyruvate through a two-step process. In the first step, alpha-ketoglutarate, ammonia and NADH are converted by the enzyme known glutamate dehydrogenase to glutamate, NAD+ and water. In the second step, the amino group of the newly-formed glutamate is transferred to pyruvate by an aminotransferase enzyme, regenerating the alpha-ketoglutarate, and converting the pyruvate to alanine. The net result is that pyruvate and ammonia are converted to alanine. In mammals, alanine plays a key role in glucose–alanine cycle between tissues and liver. In muscle and other tissues that degrade amino acids for fuel, amino groups are collected in the form of glutamate by transamination. Glutamate can then transfer its amino group to pyruvate, a product of muscle glycolysis, through the action of alanine aminotransferase, forming alanine and alpha-ketoglutarate. The alanine enters the bloodstream and is transported to the liver. The alanine aminotransferase reaction takes place in reverse in the liver, where the regenerated pyruvate is used in gluconeogenesis, forming glucose which returns to the muscles through the circulation system. Alanine is highly concentrated in muscle and is one of the most important amino acids released by muscle, functioning as a major energy source. Plasma alanine is often decreased when the BCAA (branched-chain amino acids) are deficient. This finding may relate to muscle metabolism. Alanine is highly concentrated in meat products and other high-protein foods like wheat germ and cottage cheese. Alanine is an important participant as well as a regulator of glucose metabolism. Alanine levels parallel blood sugar levels in both diabetes and hypoglycemia, and alanine is reduced in both severe hypoglycemia and the ketosis of diabetes. Alanine is an important amino acid for lymphocyte reproduction and immunity. Alanine therapy has helped dissolve kidney stones in experimental animals. Normal alanine metabolism, like that of other amino acids, is highly dependent upon enzymes that contain vitamin B6. Alanine, like GABA, taurine, and glycine, is an inhibitory neurotransmitter in the brain (http://www.dcnutrition.com/AminoAcids/).