Metabolite Spectrum Library

采用广泛MRM方法进行了代谢物参考谱图数据的采集,构建了一个包含有约14万标准品化合物的参考库







Metabolite MRM Q1 MRM Q3 RT(minutes) Adduct Struct
Hypoxanthine (BioCAD00000012307)

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.

137.0458 137.05 1.28 min [M+H]+
Citrate (BioCAD00000008630)

Citric acid (citrate) is a tricarboxylic acid, an organic acid with three carboxylate groups. Citrate is an intermediate in the TCA cycle (also known as the Tricarboxylic Acid cycle, the Citric Acid cycle or Krebs cycle). The TCA cycle is a central metabolic pathway for all animals, plants, and bacteria. As a result, citrate is found in all living organisms, from bacteria to plants to animals. In the TCA cycle, the enzyme citrate synthase catalyzes the condensation of oxaloacetate with acetyl CoA to form citrate. Citrate then acts as the substrate for the enzyme known as aconitase and is then converted into aconitic acid. The TCA cycle ends with regeneration of oxaloacetate. This series of chemical reactions in the TCA cycle is the source of two-thirds of the food-derived energy in higher organisms. Citrate can be transported out of the mitochondria and into the cytoplasm, then broken down into acetyl-CoA for fatty acid synthesis, and into oxaloacetate. Citrate is a positive modulator of this conversion, and allosterically regulates the enzyme acetyl-CoA carboxylase, which is the regulating enzyme in the conversion of acetyl-CoA into malonyl-CoA (the commitment step in fatty acid synthesis). In short, citrate is transported into the cytoplasm, converted into acetyl CoA, which is then converted into malonyl CoA by acetyl CoA carboxylase, which is allosterically modulated by citrate. In mammals and other vertebrates, Citrate is a vital component of bone, helping to regulate the size of apatite crystals (PMID: 21127269). Citric acid is found in citrus fruits, most concentrated in lemons and limes, where it can comprise as much as 8% of the dry weight of the fruit. Citric acid is a natural preservative and is also used to add an acidic (sour) taste to foods and carbonated drinks. Because it is one of the stronger edible acids, the dominant use of citric acid is as a flavoring and preservative in food and beverages, especially soft drinks and candies. Citric acid is an excellent chelating agent, binding metals by making them soluble. It is used to remove and discourage the buildup of limescale from boilers and evaporators. It can be used to treat water, which makes it useful in improving the effectiveness of soaps and laundry detergents. The salts of citric acid (citrates) can be used as anticoagulants due to their calcium chelating ability. Intolerance to citric acid in the diet is known to exist. Little information is available as the condition appears to be rare, but like other types of food intolerance it is often described as a "pseudo-allergic" reaction.

191.0197 111.01 1.22 min [M-H]-
Xanthine (BioCAD00000019451)

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.

151.0261 151.03 1.36 min [M-H]-
Alloxanthine (BioCAD00000006157)

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

151.0261 151.03 1.36 min [M-H]-
Allopurinol (BioCAD00000026108)

Allopurinol is only found in individuals that have used or taken this drug. It is a xanthine oxidase inhibitor that decreases uric acid production. It also acts as an antimetabolite on some simpler organisms. [PubChem]Allopurinol and its active metabolite, oxypurinol, inhibits the enzyme xanthine oxidase, blocking the conversion of the oxypurines hypoxanthine and xanthine to uric acid. Elevated concentrations of oxypurine and oxypurine inhibition of xanthine oxidase through negative feedback results in a decrease in the concentrations of uric acid in the serum and urine. Allopurinol also facilitates the incorporation of hypoxanthine and xanthine into DNA and RNA, leading to a feedback inhibition of de novo purin synthesis and a decrease in serum uric acid concentrations as a result of an increase in nucleotide concentration.

137.0458 137.05 1.23 min [M+H]+
Tyrosine (BioCAD00000019029)

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

182.0812 136.08 1.35 min [M+H]+
N-Acetyl-L-glutamate (BioCAD00000014537)

N-Acetyl-L-glutamic acid or N-Acetylglutamate, 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-Acetyl-L-glutamate can also be classified as an alpha amino acid or a derivatized alpha amino acid. Technically, N-Acetyl-L-glutamate is a biologically available N-terminal capped form of the proteinogenic alpha amino acid L-glutamic acid. N-Acetyl-L-glutamic acid is found in all organisms ranging from bacteria to plants to animals. 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-acetylglutamate 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 glutamic acid can also occur. In particular, N-Acetyl-L-glutamic acid can be biosynthesized from glutamate and acetylornithine by ornithine acetyltransferase, and from glutamic acid and acetyl-CoA by the enzyme known as N-acetylglutamate synthase. N-Acetyl-L-glutamic acid is the first intermediate involved in the biosynthesis of arginine in prokaryotes and simple eukaryotes and a regulator of the urea cycle in vertebrates. In vertebrates, N-acetylglutamic acid is the allosteric activator molecule to mitochondrial carbamyl phosphate synthetase I (CPSI) which is the first enzyme in the urea cycle. It triggers the production of the first urea cycle intermediate, a compound known as carbamyl phosphate. Notably the CPSI enzyme is inactive when N-acetylglutamic acid is not present. A deficiency in N-acetyl glutamate synthase or a genetic mutation in the gene coding for the enzyme will lead to urea cycle failure in which ammonia is not converted to urea, but rather accumulated in the blood leading to the condition called Type I hyperammonemia. Excessive amounts N-acetyl amino acids can be detected in the urine with individuals with aminoacylase I deficiency, a genetic disorder (PMID: 16465618). These include N-acetylalanine (as well as N-acetylserine, N-acetylglutamine, N-acetylglutamate, N-acetylglycine, N-acetylmethionine and smaller amounts of N-acetylthreonine, N-acetylleucine, N-acetylvaline and N-acetylisoleucine. Aminoacylase I is a soluble homodimeric zinc binding enzyme that catalyzes the formation of free aliphatic amino acids from N-acetylated precursors. In humans, Aminoacylase I is encoded by the aminoacylase 1 gene (ACY1) on chromosome 3p21 that consists of 15 exons (OMIM 609924). Individuals with aminoacylase I deficiency will experience convulsions, hearing loss and difficulty feeding (PMID: 16465618). ACY1 can also catalyze the reverse reaction, the synthesis of acetylated amino acids. Many N-acetylamino acids 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).

188.0564 128.04 1.27 min [M-H]-
N-acetylmuramic acid (BioCAD00000516909)

2-Acetamido-4-O-(1-carboxyethyl)-2-deoxyglucose is a natural product found in Proteus penneri with data available.

292.1038 89.02 1.25 min [M-H]-
Succinate (BioCAD00000018047)

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).

117.0193 73.03 1.35 min [M-H]-
2-Amino-3-methyl-1-butanol (BioCAD00000175058)

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

86.0964 69.07 1.36 min [M+H-H2O]+
Methylmalonate (BioCAD00000014053)

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.

117.0193 73.03 1.35 min [M-H]-
D-Isoleucine (BioCAD00000009393)

The D-enantiomer of isoleucine." []

132.1019 86.1 1.25 min [M+H]+
Taurine (BioCAD00000018209)

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.

124.0074 124.01 1.35 min [M-H]-
cyclo(L-His-L-Pro) (BioCAD00000492881)

A homodetic cyclic peptide resulting from the formal condensation of both the amino and acid groups of L-histidine with the acid and amino groups of L-proline. It is a metabolite of thyrotropin-releasing hormone (TRH)." []

235.1189 235.12 1.23 min [M+H]+
Cyclo(his-pro) (BioCAD00000179697)

Cyclo(L-His-L-Pro) is a homodetic cyclic peptide resulting from the formal condensation of both the amino and acid groups of L-histidine with the acid and amino groups of L-proline. It is a metabolite of thyrotropin-releasing hormone (TRH). It has a role as a human blood serum metabolite, a dopamine uptake inhibitor and an anti-inflammatory agent. It is a homodetic cyclic peptide, a dipeptide, a pyrrolopyrazine and a member of imidazoles. It is functionally related to a L-histidine and a L-proline.

235.1189 235.12 1.23 min [M+H]+
Urocanate (BioCAD00000019212)

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).

139.0502 139.05 1.3 min [M+H]+
N-Acetylmuramate (BioCAD00000014577)

This compound belongs to the family of N-acyl-alpha-hexosamines. These are carbohydrate derivatives containing a hexose moeity in which the oxygen atom is replaced by an n-acyl group.

292.1038 89.02 1.25 min [M-H]-
Maltose (BioCAD00000013694)

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.

341.1089 89.02 1.29 min [M-H]-
Palatinose (BioCAD00000015820)

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." []

341.1089 89.02 1.29 min [M-H]-
Threonate (BioCAD00000018545)

Threonic acid, also known as threonate, belongs to the class of organic compounds known as sugar acids and derivatives. Sugar acids and derivatives are compounds containing a saccharide unit which bears a carboxylic acid group. Threonic acid is a sugar acid derived from threose. The L-isomer is a metabolite of ascorbic acid (vitamin C). One study suggested that because L-threonate inhibits DKK1 expression in vitro, it may have potential in the treatment of androgenic alopecia (PMID:21034532). Threonic acid is probably derived from glycated proteins or from degradation of ascorbic acid. It is a normal component in aqueous humour and blood (PMID:10420182). Threonic acid is a substrate of L-threonate 3-dehydrogenase (EC 1.1.1.129) in the ascorbate and aldarate metabolism pathway (KEGG). It has been found to be a microbial metabolite (PMID:20615997).

135.0299 135.03 1.26 min [M-H]-
D-Tyrosine (BioCAD00000009466)

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

180.0666 180.07 1.33 min [M-H]-
N-Acetylglutamic acid (BioCAD00000778446)

188.0564 102.06 1.27 min [M-H]-
3-Amino-3-(4-hydroxyphenyl)propanoate (BioCAD00000003366)

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).

180.0666 180.07 1.33 min [M-H]-
Choline phosphate (BioCAD00000384447)

Phosphorylcholine is a natural product found in Homo sapiens with data available. Calcium and magnesium salts used therapeutically in hepatobiliary dysfunction.

184.0733 184.07 1.25 min [M+H]+
5-Ureido-4-imidazole carboxylate (BioCAD00000004946)

An imidazole-4-carboxylic acid compound having a ureido substituent at the 5-position." []

151.0261 42 1.36 min [M-H-H2O]-
Succinis acid (BioCAD00000781417)

117.0193 73.03 1.27 min [M-H]-
Isoleucine (not validated) (BioCAD00000781640)

132.1019 86.1 1.25 min [M+H]+
4-Nitroaniline (BioCAD00000004479)

A nitroaniline carrying a nitro group at position 4." []

139.0502 139.05 1.3 min [M+H]+
Gynocardin (BioCAD00000011916)

Gynocardin is found in fruits. Glucoside from Pangium edule (football fruit

286.0921 124.04 1.24 min [M+H-H2O]+
para-Benzoquinone dioxime (BioCAD00000015868)

139.0502 121.04 1.3 min [M+H]+