Rat Cystathionine Β-synthase, CBS ELI

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 (By similarity).

Also involved in the production of hydrogen sulfide, a gasotransmitter with signaling and cytoprotective effects on neurons (PubMed: 201$498.00|$360.0043, PubMed: 8558235).