Alliinase (alliin lyase; EC 4.4.1.4) from Allium sativum L. (garlic) (Alliinase)

Alliinase is a major pyridoxal phosphate (PLP)-dependent enzyme found in garlic (Allium sativum L.) bulbs, where it serves as a key component in the biosynthesis of allicin, the organosulfur compound responsible for garlic's characteristic aroma and many of its medicinal properties[1]. Unlike a membrane receptor or channel, alliinase is a soluble, homodimeric glycoprotein with N-linked oligosaccharides. When garlic cloves are crushed or injured, the enzyme is released from cell vacuoles and converts the precursor alliin into allicin, which is produced only transiently and breaks down rapidly into other sulfur-containing compounds (e.g., diallyl disulfide, ajoenes)[2]. Allicin, along with its breakdown products, is responsible for much of garlic's antimicrobial, antioxidant, and pharmacologic effects, and these compounds are under investigation for their potential therapeutic roles in cardiovascular disease, infection, inflammation, and metabolic disorders[3]. Alliinase is not itself a therapeutic target in the classic sense, but rather a catalyst for the formation of bioactive compounds such as allicin, which have biologic activity. The enzyme's structure (PDB: 2HOX) has been crystallographically resolved, revealing details of its active site, cofactor (PLP) binding, and reaction intermediates[1].

Other names

Alliin lyaseallyl-sulfenate lyasepyridoxal phosphate-dependent alliinasegarlic alliinase(+S)-allyl-L-cysteine sulfoxide lyase

Catalyzes the conversion of alliin ((+S)-allyl-L-cysteine sulfoxide) to allicin (diallyl thiosulfinate), pyruvate, and ammonia; cleavage of S-allyl-L-cysteine sulfoxide via an alpha, beta-lyase (elimination) reaction[1]