Alliinase: A Comprehensive Review of the Pivotal Enzyme in Garlic Chemistry and Its Applications

Alliinase is a pyridoxal 5′‐phosphate (PLP)‐dependent lyase that serves as the cornerstone of the defense system in plants of the Allium genus such as garlic. Upon tissue damage, this pivotal enzyme catalyzes the hydrolysis of odorless, nonvolatile S ‐alk(en)yl‐ l ‐cysteine sulfoxides (e.g., alliin) into volatile, bioactive organosulfur compounds, most notably allicin, which is responsible for garlic's distinctive aroma and its wide‐ranging medicinal properties, including antimicrobial and antioxidant effects. This review comprehensively summarizes the current knowledge on the enzyme's discovery, molecular structure, biochemical properties including substrate specificity, pH/thermal stability, and sensitivity to metal ions, three‐dimensional structure, reaction mechanism, genetic regulation, isolation, and immobilization. Harnessing alliinase extracted directly from garlic is significantly challenged by its low yield and inherent instability. To address these limitations, this review details recent advances in enhancing enzyme availability through heterologous expression and improving operational stability via immobilization on various supports, such as chitosan, alginate, and synthetic polymers. Furthermore, it explores the broad applications of alliinase across the food, pharmaceutical, and biotechnology industries, particularly in the production of allicin and related bioactive compounds. Finally, the review outlines future research directions, emphasizing the potential of protein engineering, advanced expression systems, and novel immobilization strategies to fully unlock the industrial potential of this versatile enzyme.