Exact Mass: 196.0558
Exact Mass Matches: 196.0558
Found 290 metabolites which its exact mass value is equals to given mass value 196.0558,
within given mass tolerance error 0.01 dalton. Try search metabolite list with more accurate mass tolerance error
0.001 dalton.
1,7-dimethylurate
1,7 dimethyluric acid is the major urinary caffeine metabolites that is produced in the human body. 1,7 dimethyluric acid is formed during metabolism of caffeine and the process is catalyzed primarily by CYP2A6. (PMID: 18715882) [HMDB] 1,7-Dimethyluric acid is the major urinary caffeine metabolite that is produced in the human body. 1,7-Dimethyluric acid is formed during caffeine metabolism and the process is catalyzed primarily by CYP2A6 (PMID: 18715882).
3,7-Dimethyluric acid
3,7-Dimethyluric acid is a methyl derivative of uric acid, found occasionally in human urine. 3,7-Dimethyluric is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis. (PMID: 11712316, 15833286, 3506820, 15013152) [HMDB] 3,7-Dimethyluric acid is a methyl derivative of uric acid, found occasionally in human urine. 3,7-Dimethyluric is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis (PMID:11712316, 15833286, 3506820, 15013152).
Gluconic acid
Gluconic acid, also known as D-gluconic acid, D-gluconate or (2R,3S,4R,5R)-2,3,4,5,6-pentahydroxyhexanoic acid (also named dextronic acid), is the C1-oxidized form of D-glucose where the aldehyde group has become oxidized to the corresponding carboxylic acid. Gluconic acid 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. In aqueous solution, gluconic acid exists in equilibrium with the cyclic ester glucono delta-lactone. Gluconic acid occurs naturally in fruit, honey, kombucha tea and wine. The salts of gluconic acid are known as "gluconates". Gluconic acid, gluconate salts, and gluconate esters occur widely in nature because such species arise from the oxidation of glucose. Gluconic acid exists in all living species, ranging from bacteria to plants to humans. The metabolism of gluconate is well characterized in prokaryotes where it is known to be degraded following phosphorylation by gluconokinase. Glucokinase activity has also been detected in mammals, including humans (PMID: 24896608). Gluconic acid is produced in the gluconate shunt pathway. In the gluconate shunt, glucose is oxidized by glucose dehydrogenase (also called glucose oxidase) to furnish gluconate, the form in which D-gluconic acid is present at physiological pH. Subsequently, gluconate is phosphorylated by the action of gluconate kinase to produce 6-phosphogluconate, which is the second intermediate of the pentose phosphate pathway. This gluconate shunt is mainly found in plants, algae, cyanobacteria and some bacteria, which all use the Entner–Doudoroff pathway to degrade glucose or gluconate; this generates 2-keto-3-deoxygluconate-6-phosphate, which is then cleaved to generate pyruvate and glyceraldehyde 3-phosphate. Glucose dehydrogenase and gluconate kinase activities are also present in mammals, fission yeast, and flies. Gluconic acid has many industrial uses. It is used as a drug as part of electrolyte supplementation in total parenteral nutrition. It is also used in cleaning products where it helps cleaning up mineral deposits. Gluconic acid or Gluconic acid is used to maintain the cation-anion balance on electrolyte solutions. In humans, gluconic acid is involved in the metabolic disorder called the transaldolase deficiency. Gluconic acid has been found to be a metabolite in Aspergillus (Hugo Vanden Bossche, D.W.R. Mackenzie and G. Cauwenbergh. Aspergillus and Aspergillosis, 1987). [Spectral] D-Gluconic acid (exact mass = 196.0583) and Guanine (exact mass = 151.04941) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. Dietary supplement, acidity regulator approved in Japan. Component of bottle rinsing formulations Acquisition and generation of the data is financially supported in part by CREST/JST. KEIO_ID G031
Galactonate
Galactonic acid is a sugar acid that is a metabolic breakdown product of galactose. Galactose dehydrogenase is responsible for converting galactose to galactonolactone, which then spontaneously or enzymatically converts to galactonic acid. Once formed, galactonic acid may enter the pentose phosphate pathway. Galactonic acid is increased in red blood cells of galactosemic patients, due to a galactose-1-phosphate uridyltransferase (GALT) deficiency (PMID: 14680973, OMMBID: The Online Metabolic and Molecular Bases of Inherited Disease, Ch.72). When present in sufficiently high levels, galactonic 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 galactonic acid are associated with at least two inborn errors of metabolism, including galactosemia and galactosemia type II. Galactonic acid is an organic acid. 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, liver abnormalities (jaundice), kidney abnormalities, seizures, coma, and possibly death. These are also the characteristic symptoms of untreated galactosemia. Many affected children with organic acidemias experience intellectual disability or delayed development. High levels of galactonic acid in infants are specifically associated with hepatomegaly (an enlarged liver), cirrhosis, renal failure, cataracts, vomiting, seizure, hypoglycemia, lethargy, brain damage, and ovarian failure. Galactonate is increased in red blood cells of galactosemic patients, due to a galactose-1-phosphate uridyltransferase (GALT) deficiency ((PMID 14680973, OMMBID: The Metabolic and Molecular Bases of Inherited Disease, Ch.72) [HMDB]
Gulonate
Gulonic acid, also known as gulonate, belongs to the class of organic compounds known as medium-chain hydroxy acids and derivatives. These are hydroxy acids with a 6 to 12 carbon atoms long side chain.It is a gulonic acid having D-configuration. Reduction product of glucuronic acid; oxidation product of l-gulose [HMDB]
Xanthone
Xanthone is the parent compound of the xanthone class consisting of xanthene bearing a single oxo substituent at position 9. It has a role as an insecticide. Xanthone is a natural product found in Harungana madagascariensis, Garcinia dulcis, and other organisms with data available. Xanthone is isolated from Mangosteen and is known to control cell division and growth, apoptosis, inflammation, and metastasis in different stages of carcinogenesis. Xanthone has anti-oxidant, anti-tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities[1]. Xanthone is isolated from Mangosteen and is known to control cell division and growth, apoptosis, inflammation, and metastasis in different stages of carcinogenesis. Xanthone has anti-oxidant, anti-tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities[1].
1,3-dimethylurate
1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis. (PMID: 11712316, 15833286, 3506820, 15013152, 4039734) [HMDB] 1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis. (PMID:11712316, 15833286, 3506820, 15013152, 4039734). 1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi.
1,9-Dimethyluric acid
1,9-Dimethyluric acid is a methyl derivative of uric acid, found occasionally in human urine. 1,9-Methyluracil is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis. (PMID: 11712316, 15833286, 3506820, 15013152) [HMDB] 1,9-Dimethyluric acid is a methyl derivative of uric acid, found occasionally in human urine. 1,9-Methyluracil is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis. (PMID:11712316, 15833286, 3506820, 15013152).
3,9-Dimethyluric acid
3,9-Dimethyluric acid is involved in purine oxidation pathways. Reevaluation of products derived from 3,9-dimethyluric acid in a chlorination-reductive dechlorinaton sequence has demonstrated unequivocally that they are not purines.(PMID 14601976)
7,9-Dimethyluric acid
7,9-Dimethyluric acid is a methyl derivative of uric acid, found occasionally in human urine. 7,9-Dimethyluracil is one of the purine component in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. (PMID: 11712316, 15833286, 3506820) [HMDB] 7,9-Dimethyluric acid is a methyl derivative of uric acid, found occasionally in human urine. 7,9-Dimethyluracil is one of the purine component in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. (PMID: 11712316, 15833286, 3506820).
XANTHONE
Xanthone is isolated from Mangosteen and is known to control cell division and growth, apoptosis, inflammation, and metastasis in different stages of carcinogenesis. Xanthone has anti-oxidant, anti-tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities[1]. Xanthone is isolated from Mangosteen and is known to control cell division and growth, apoptosis, inflammation, and metastasis in different stages of carcinogenesis. Xanthone has anti-oxidant, anti-tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities[1].
2-Carboxyarabinitol
2-carboxyarabinitol is a member of the class of compounds known as hydroxy fatty acids. Hydroxy fatty acids are fatty acids in which the chain bears a hydroxyl group. 2-carboxyarabinitol is soluble (in water) and a weakly acidic compound (based on its pKa). 2-carboxyarabinitol can be found in a number of food items such as tarragon, dandelion, ginkgo nuts, and spinach, which makes 2-carboxyarabinitol a potential biomarker for the consumption of these food products.
Xanthone
CONFIDENCE standard compound; INTERNAL_ID 198; DATASET 20200303_ENTACT_RP_MIX501; DATA_PROCESSING MERGING RMBmix ver. 0.2.7; DATA_PROCESSING PRESCREENING Shinyscreen ver. 0.8.0; ORIGINAL_ACQUISITION_NO 9192; ORIGINAL_PRECURSOR_SCAN_NO 9189 CONFIDENCE standard compound; INTERNAL_ID 198; DATASET 20200303_ENTACT_RP_MIX501; DATA_PROCESSING MERGING RMBmix ver. 0.2.7; DATA_PROCESSING PRESCREENING Shinyscreen ver. 0.8.0; ORIGINAL_ACQUISITION_NO 9263; ORIGINAL_PRECURSOR_SCAN_NO 9262 CONFIDENCE standard compound; INTERNAL_ID 198; DATASET 20200303_ENTACT_RP_MIX501; DATA_PROCESSING MERGING RMBmix ver. 0.2.7; DATA_PROCESSING PRESCREENING Shinyscreen ver. 0.8.0; ORIGINAL_ACQUISITION_NO 9233; ORIGINAL_PRECURSOR_SCAN_NO 9231 CONFIDENCE standard compound; INTERNAL_ID 198; DATASET 20200303_ENTACT_RP_MIX501; DATA_PROCESSING MERGING RMBmix ver. 0.2.7; DATA_PROCESSING PRESCREENING Shinyscreen ver. 0.8.0; ORIGINAL_ACQUISITION_NO 9258; ORIGINAL_PRECURSOR_SCAN_NO 9255 CONFIDENCE standard compound; INTERNAL_ID 198; DATASET 20200303_ENTACT_RP_MIX501; DATA_PROCESSING MERGING RMBmix ver. 0.2.7; DATA_PROCESSING PRESCREENING Shinyscreen ver. 0.8.0; ORIGINAL_ACQUISITION_NO 9245; ORIGINAL_PRECURSOR_SCAN_NO 9242 CONFIDENCE standard compound; INTERNAL_ID 198; DATASET 20200303_ENTACT_RP_MIX501; DATA_PROCESSING MERGING RMBmix ver. 0.2.7; DATA_PROCESSING PRESCREENING Shinyscreen ver. 0.8.0; ORIGINAL_ACQUISITION_NO 9280; ORIGINAL_PRECURSOR_SCAN_NO 9279 Xanthone is isolated from Mangosteen and is known to control cell division and growth, apoptosis, inflammation, and metastasis in different stages of carcinogenesis. Xanthone has anti-oxidant, anti-tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities[1]. Xanthone is isolated from Mangosteen and is known to control cell division and growth, apoptosis, inflammation, and metastasis in different stages of carcinogenesis. Xanthone has anti-oxidant, anti-tumor, anti-allergic, anti-inflammatory, anti-bacterial, anti-fungal, and anti-viral activities[1].
2-Hydroxyphenazine
CONFIDENCE standard compound; INTERNAL_ID 185 INTERNAL_ID 185; CONFIDENCE standard compound
1,2-Dihydroxy-tridecapentain-(3,5,7,9,11)|3,5,7,9,11-Tridecapentayne-1,2-diol|trideca-3,5,7,9,11-pentayne-1,2-diol|Tridecapentain-(3,5,7,9,11)-diol-(1,2)
1,3-Dimethylurate
Acquisition and generation of the data is financially supported in part by CREST/JST. 1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi.
1,9-Dimethyluric acid
relative retention time with respect to 9-anthracene Carboxylic Acid is 0.252 relative retention time with respect to 9-anthracene Carboxylic Acid is 0.253 relative retention time with respect to 9-anthracene Carboxylic Acid is 0.246 relative retention time with respect to 9-anthracene Carboxylic Acid is 0.247
4-Fluorobenzoylpropionic acid
CONFIDENCE standard compound; INTERNAL_ID 2724 CONFIDENCE Reference Standard (Level 1); INTERNAL_ID 8543
1,3-Dimethyluric acid
An oxopurine that is 7,9-dihydro-1H-purine-2,6,8(3H)-trionesubstituted by methyl groups at N-1 and N-3. 1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi.
3,7-Dimethyluric acid
An oxopurine that is 7,9-dihydro-1H-purine-2,6,8(3H)-trione substituted by methyl groups at N-3 and N-7.
1,7-Dimethyluric acid
An oxopurine that is 7,9-dihydro-1H-purine-2,6,8(3H)-trione substituted by methyl groups at N-1 and N-7. It is a metabolite of caffeine and is often found in human urine samples.
Oxytheophylline
1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi.
6-methyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylic acid
5-methyl-4,5,6,7-tetrahydro-1-benzothiophene-2-carboxylic acid
3-Pyridinecarbonitrile,1,2-dihydro-2-oxo-5-phenyl-
6-METHYL-4,5,6,7-TETRAHYDROBENZO[B]THIOPHENE-2-CARBOXYLIC ACID
5-Chloro-4,6-dimethyl-2H-pyrazolo[3,4-b]pyridin-3-amine
3-Pyridinecarbonitrile,1,2-dihydro-2-oxo-6-phenyl-
2,3-Dihydro-2,3-dimethyl-benzo[b]thiophene 1,1-dioxide
6-Fluoro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid
5,6,7,8-Tetrahydro-4H-cyclohepta[b]thiophene-2-carboxylic acid
Methyl 4,5,6,7-tetrahydro-1-benzothiophene-2-carboxylate
(2R)-6-fluoro-3,4-dihydro-2H-chromene-2-carboxylic acid
methyl (2R)-2,5-diamino-5-oxopentanoate,hydrochloride
5-fluoro-2-methyl-3-methylsulfanyl-1H-pyrrolo[2,3-b]pyridine
Quinoxaline, 2-chloro-3-hydrazino-1,4-dihydro- (9CI)
4,6-Pyrimidinedicarboxylicacid, 4,6-dimethyl ester
2-Pyridinecarboxylicacid,3-methyl-6-nitro-,methylester(9CI)
Hydralazine hydrochloride
C78274 - Agent Affecting Cardiovascular System > C270 - Antihypertensive Agent D002317 - Cardiovascular Agents > D000959 - Antihypertensive Agents D002317 - Cardiovascular Agents > D014665 - Vasodilator Agents
4-chloro-alpha-cyclopropyl-alpha-methylbenzyl alcohol
7,9-Dihydro-3,9-dimethyl-1H-purine-2,6,8(3H)-trione
6H-Dibenzo[b,d]pyran-6-one
A benzochromenone that is 6H-dibenzo[b,d]pyran substituted by an oxo group at position 6.
(5R)-5-[(1E)-Buta-1,3-dienyl]-4-hydroxy-3,5-dimethylthiophen-2(5H)-one
L-dopa(1-)
A L-alpha-amino acid anion which is the conjugate base of L-dopa, obtained by deprotonation of the carboxy group: major species at pH 7.3.
L-Gulonic acid
A gulonic acid formed by oxidising the aldehyde group of L-gulose to a carboxylic acid group.
