Figure 1
From: A Comparison of the Antibacterial and Antifungal Activities of Thiosulfinate Analogues of Allicin

Biosynthesis of allicin from S-allyl cysteine sulfoxide (alliin). The enzyme alliinase (a C-S lyase, E.C. 4.4.1.4.) catalyzes the formation of allylsulfenic acid and dehydroalanine (a), whereupon two molecules of allylsulfenic acid condense spontaneously to yield one molecule of allicin (b).