Target type: molecularfunction
Catalysis of the reaction: L-serine + L-homocysteine = cystathionine + H2O. [EC:4.2.1.22]
Cystathionine beta-synthase (CBS) activity is a crucial enzymatic process involved in the transsulfuration pathway, a metabolic pathway responsible for the conversion of homocysteine to cysteine. CBS catalyzes the condensation of serine and homocysteine to form cystathionine. This reaction utilizes pyridoxal 5'-phosphate (PLP) as a cofactor. The enzyme's active site specifically binds both substrates, positioning them for the PLP-dependent reaction. The catalytic mechanism involves the formation of a Schiff base between PLP and the amino group of serine, followed by a series of steps that ultimately lead to the transfer of the sulfur atom from homocysteine to serine, resulting in the production of cystathionine. CBS activity is essential for maintaining appropriate levels of homocysteine in the body. Elevated homocysteine levels are linked to a range of cardiovascular diseases, neurological disorders, and other health problems. Moreover, CBS activity is involved in the regulation of sulfur metabolism and the biosynthesis of cysteine, an essential amino acid required for various cellular processes, including protein synthesis, antioxidant defense, and glutathione production.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Cystathionine beta-synthase | A cystathionine beta-synthase that is encoded in the genome of human. [PRO:DNx, UniProtKB:P35520] | 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 |
| 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 | |||
| 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 |