Homocysteine/cysteine synthase

UniProtKB accession:  P06106

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Catalyzes the conversion of O-acetyl-L-homoserine (OAH) into homocysteine in the methionine biosynthesis pathway (PubMed:7765825, PubMed:4609980, PubMed:795806, PubMed:36455053, PubMed:36379252). Required to efficiently reduce toxic levels of hydrogen sulfide generated when the sulfate assimilation pathway (SAP) is active (PubMed:36455053, PubMed:36379252). Also catalyzes the conversion of O-acetylserine (OAS) into cysteine, the last step in the cysteine biosynthesis pathway (PubMed:7765825, PubMed:4609980, PubMed:795806, PubMed:36455053). However, it seems that in S.cerevisiae cysteine biosynthesis occurs exclusively through the cystathionine pathway and not via direct incorporation of sulfur into OAS (PubMed:1732168). It therefore has no metabolic role in cysteine biosynthesis and may only have a regulatory role controlling OAS levels (PubMed:12586406).