A thioglucosidase in fungi

A β-thioglucosidase capable of hydrolyzing mustard oil glucosides is of rare occurrence in fungi. Aspergillus sydowi QM 31c is a good source of the enzyme. The fungal enzyme resembles mustard seed myrosinase. Both enzymes degrade sinigrin producing glucose, KHSO 4, and allyl isothiocyanate. They attack only the mustard oil thioglucosides, and are inactive on thioglucosides not having this configuration. The fungal enzyme is relatively more active on sinalbin and glucotropaeolin than is myrosinase. The fungal enzyme is less resistant to heat, acids, alkalies, and chemical inhibitors than is the mustard enzyme.