Alliinase

In enzymology, an alliin lyase (EC4.4.1.4) is an enzyme that catalyzes the chemical reaction

an S-alkyl-L-cysteine S-oxide ${\displaystyle ightleftharpoons }$ an alkyl sulfenate + 2-aminoacrylate

Hence, this enzyme has one substrate, 2 molecules of an S-alkyl-L-cysteineS-oxide, and two products, 1 molecule each of a alkyl sulfenate and 2-aminoacrylate. The prototypical example is conversion of alliin into allicin, hence the name. This enzyme is a carbon-sulfur lyase (it breaks a C-S bond).

This enzyme is found in plants of the genus Allium, such as garlic and onions. Alliinase is responsible for catalyzing chemical reactions that produce the volatile chemicals that give these foods their flavors, odors, and tear-inducing properties.

The systematic name of this enzyme class is S-alkyl-L-cysteine S-oxide alkyl-sulfenate-lyase (2-aminoacrylate-forming). Other names in common use include alliinase, cysteine sulfoxide lyase, alkylcysteine sulfoxide lyase, S-alkylcysteine sulfoxide lyase, L-cysteine sulfoxide lyase, S-alkyl-L-cysteine sulfoxide lyase, and alliin alkyl-sulfenate-lyase. It employs one cofactor, pyridoxal phosphate (the active form of vitamin B6).