Target type: biologicalprocess
The interconversion of homocysteine and cysteine via cystathionine. In contrast with enteric bacteria and mammals, Saccharomyces cerevisiae has two transsulfuration pathways employing two separate sets of enzymes. [MetaCyc:PWY-801]
Transsulfuration is a metabolic pathway that converts homocysteine to cysteine. This pathway is essential for the synthesis of cysteine, a sulfur-containing amino acid that is required for the production of proteins, glutathione, and other important molecules. The transsulfuration pathway is also involved in the detoxification of homocysteine, a toxic amino acid that can damage blood vessels and contribute to heart disease.
The transsulfuration pathway begins with the conversion of homocysteine to cystathionine by the enzyme cystathionine beta-synthase (CBS). Cystathionine is then converted to cysteine by the enzyme cystathionine gamma-lyase (CSE). The first step in the pathway, the conversion of homocysteine to cystathionine, is the rate-limiting step. This step is regulated by a number of factors, including the availability of vitamin B6, folate, and sulfur-containing amino acids.
The transsulfuration pathway is important for a number of reasons. First, it is essential for the synthesis of cysteine, a crucial amino acid. Second, the pathway plays a role in the detoxification of homocysteine, a toxic amino acid that can contribute to heart disease. Third, the transsulfuration pathway is linked to the metabolism of other sulfur-containing compounds, such as methionine and taurine.
Genetic defects in the transsulfuration pathway can lead to a number of diseases, including homocystinuria. Homocystinuria is a rare genetic disorder that causes elevated levels of homocysteine in the blood. The buildup of homocysteine in the blood can lead to a number of health problems, including heart disease, stroke, and developmental delays.
The transsulfuration pathway is a complex and important metabolic pathway that plays a role in the synthesis of cysteine, the detoxification of homocysteine, and the metabolism of other sulfur-containing compounds.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Cystathionine beta-lyase MetC | A cystathionine beta-lyase MetC that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P06721] | Escherichia coli K-12 |
| Cystathionine beta-synthase | A cystathionine beta-synthase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P35520] | Homo sapiens (human) |
| Cystathionine gamma-lyase | A cystathionine gamma-lyase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P32929] | Homo sapiens (human) |
| C-1-tetrahydrofolate synthase, cytoplasmic | A C-1-tetrahydrofolate synthase, cytoplasmic that is encoded in the genome of human. [PRO:DNx, UniProtKB:P11586] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| aminooxyacetic acid | (aminooxy)acetic acid : A member of the class of hydroxylamines that is acetic acid substituted at postion 2 by an aminooxy group. It is a compound which inhibits aminobutyrate aminotransferase activity in vivo, resulting in increased levels of gamma-aminobutyric acid in tissues. Aminooxyacetic Acid: A compound that inhibits aminobutyrate aminotransferase activity in vivo, thereby raising the level of gamma-aminobutyric acid in tissues. | amino acid; hydroxylamines; monocarboxylic acid | anticonvulsant; EC 2.6.1.19 (4-aminobutyrate--2-oxoglutarate transaminase) inhibitor; EC 4.2.1.22 (cystathionine beta-synthase) inhibitor; nootropic agent |
| salicylic acid | Scalp: The outer covering of the calvaria. It is composed of several layers: SKIN; subcutaneous connective tissue; the occipitofrontal muscle which includes the tendinous galea aponeurotica; loose connective tissue; and the pericranium (the PERIOSTEUM of the SKULL). | monohydroxybenzoic acid | algal metabolite; antifungal agent; antiinfective agent; EC 1.11.1.11 (L-ascorbate peroxidase) inhibitor; keratolytic drug; plant hormone; plant metabolite |
| aurintricarboxylic acid | aurintricarboxylic acid : A member of the class of quinomethanes that is 3-methylidene-6-oxocyclohexa-1,4-diene-1-carboxylic acid in which the methylidene hydrogens are replaced by 4-carboxy-3-hydroxyphenyl groups. The trisodium salt is the biological stain 'chrome violet CG' while the triammonium salt is 'aluminon'. Aurintricarboxylic Acid: A dye which inhibits protein biosynthesis at the initial stages. The ammonium salt (aluminon) is a reagent for the colorimetric estimation of aluminum in water, foods, and tissues. | monohydroxybenzoic acid; quinomethanes; tricarboxylic acid | fluorochrome; histological dye; insulin-like growth factor receptor 1 antagonist |
| hypericin | |||
| mesalamine | mesalamine : A monohydroxybenzoic acid that is salicylic acid substituted by an amino group at the 5-position. Mesalamine: An anti-inflammatory agent, structurally related to the SALICYLATES, which is active in INFLAMMATORY BOWEL DISEASE. It is considered to be the active moiety of SULPHASALAZINE. (From Martindale, The Extra Pharmacopoeia, 30th ed) | amino acid; aromatic amine; monocarboxylic acid; monohydroxybenzoic acid; phenols | non-steroidal anti-inflammatory drug |
| penicillamine | penicillamine : An alpha-amino acid having the structure of valine substituted at the beta position with a sulfanyl group. Penicillamine: 3-Mercapto-D-valine. The most characteristic degradation product of the penicillin antibiotics. It is used as an antirheumatic and as a chelating agent in Wilson's disease. | non-proteinogenic alpha-amino acid; penicillamine | antirheumatic drug; chelator; copper chelator; drug allergen |
| 4-toluenesulfonyl hydrazide | |||
| nitroxoline | nitroxoline : A monohydroxyquinoline in which the hydroxy group is positioned at C-8 with a nitro group trans to it at C-5. nitroxoline: structure in Merck Index, 9th ed, #6475; RN given refers to parent cpd | C-nitro compound; monohydroxyquinoline | antifungal agent; antiinfective agent; antimicrobial agent; renal agent |
| olsalazine | olsalazine : An azobenzene that consists of two molecules of 4-aminosalicylic acid joined by an azo linkage. A prodrug for mesalazine, an anti-inflammatory drug, it is used (as the disodium salt) in the treatment of inflammatory bowel disease. olsalazine: cpd with 2 salicylate molecules linked together by an azo bond | azobenzenes; dicarboxylic acid | non-steroidal anti-inflammatory drug; prodrug |
| methyldopa | alpha-methyl-L-dopa : A derivative of L-tyrosine having a methyl group at the alpha-position and an additional hydroxy group at the 3-position on the phenyl ring. Methyldopa: An alpha-2 adrenergic agonist that has both central and peripheral nervous system effects. Its primary clinical use is as an antihypertensive agent. | L-tyrosine derivative; non-proteinogenic L-alpha-amino acid | alpha-adrenergic agonist; antihypertensive agent; hapten; peripheral nervous system drug; sympatholytic agent |
| 6-amino-7-chloro-5,8-dioxoquinoline | 6-amino-7-chloro-5,8-dioxoquinoline: quinone structure important in this cpd; structure | ||
| kalafungin | kalafungin: nanaomycin D from Streptomyces rosa & is enantiomer of kalafungin; RN given refers to (3aR-(3aalpha,5alpha,11balpha))-isomer; see also nanaomycin C; structure of kalafungin in first source; structure of nanaomycin in second source | ||
| nsc228155 | |||
| agathisflavone | agathisflavone : A biflavonoid that is obtained by oxidative coupling of two molecules of apigenin resulting in a bond between positions C-6 and C-8 of the two chromene rings. agathisflavone: bis-apigenin coupled at 6 and 8 positions; isolated from the plant Canarium manii; has hepatoprotective activity against carbon tetrachloride-induced hepatotoxicity | biaryl; biflavonoid; hydroxyflavone | antineoplastic agent; antiviral agent; hepatoprotective agent; metabolite |
| cupressuflavone | cupressuflavone : A biflavonoid that is obtained by oxidative coupling of two molecules of apigenin resulting in a bond between positions C-8 of the two chromene rings respectively. Isolated from Cupressus sempervirens and Juniperus occidentalis, it exhibits free radical scavenging and antielastase activities. cupressuflavone: from Cupressus macrocarpa; structure in first source | biflavonoid; hydroxyflavone; ring assembly | EC 3.4.21.37 (leukocyte elastase) inhibitor; metabolite; radical scavenger |
| myricetin | 7-hydroxyflavonol; hexahydroxyflavone | antineoplastic agent; antioxidant; cyclooxygenase 1 inhibitor; food component; geroprotector; hypoglycemic agent; plant metabolite | |
| podocarpusflavone a | podocarpusflavone A: isolated from Podocarpus imbricatus | flavonoid oligomer | |
| rubrolide a | rubrolide A: from Synoicum prunum; structure in first source | ||
| aminoethoxyvinylglycine | aminoethoxyvinylglycine: RN given for (S-(E))-isomer | ||
| 5-methyltetrahydrohomofolic acid | 5-methyltetrahydrohomofolic acid: RN given refers to parent cpd |