Myrosinase is a β-thioglucosidase enzyme (EC 3.2.1.147) primarily found in Brassicaceae plants such as mustard, horseradish, broccoli, and wasabi. It catalyzes the hydrolysis of glucosinolates, releasing glucose, bisulfate, and bioactive products including isothiocyanates responsible for pungent flavors and aromas. The enzyme is compartmentalized separately from substrates in intact plant cells and activates upon tissue damage. It often requires ascorbic acid as a cofactor and exists as a glycoprotein with molecular weights typically 120-200 kDa depending on source and multimeric state. Heat-labile and inactivated by cooking, it plays roles in plant defense and contributes to potential health benefits via isothiocyanate formation.