| Primary Identifier | IPR005857 | Type | Family |
| Short Name | Cysta_beta_synth |
| description | Members of this family closely resemble cysteine synthase but contain an additional C-terminal CBS domain. Cysteine synthase (O-acetylserine (thiol)-lyase) is the enzyme responsible for the formation of cysteine from O-acetyl-serine and hydrogen sulphide with the concomitant release of acetic acid - the function of many of these enzymes is unproven.This entry includes human CBS protein, which is a hydro-lyase catalyzing the first step of the transsulfuration pathway, where the hydroxyl group of L-serine is displaced by L-homocysteine in a beta-replacement reaction to form L-cystathionine, the precursor of L-cysteine. This catabolic route allows the elimination of L-methionine and the toxic metabolite L-homocysteine [, , ]. Mutations in the CBS gene cause cystathionine beta-synthase deficiency (CBSD), an enzymatic deficiency resulting in altered sulfur metabolism and homocystinuria [, ]. |
