Myrosinase (EC 3.2.1.147, thioglucoside glucohydrolase, sinigrinase, and sinigrase) is a family of enzymes involved in plant defense against herbivores, specifically the mustard oil bomb.

The remaining molecule then quickly converts to a thiocyanate, an isothiocyanate, or a nitrile; these are the active substances that serve as defense for the plant.

The hydrolysis of glucosinolates by myrosinase can yield a variety of products, depending on various physiological conditions such as pH and the presence of certain cofactors.

The last step in the mechanism is subject to the greatest variety depending on the physiological conditions under which the reaction takes place.

Under acidic conditions (pH < 3), and in the presence of ferrous ions or epithiospecifer proteins, the formation of nitriles is favored instead.

[4] In addition, 2-F-2-deoxybenzylglucosinolate, which was synthesized specifically to study the mechanism of myrosinase, inhibits the enzyme by trapping one of the glutamic acid residues in the active site, Glu 409.

[9] [10] X-ray crystallography of myrosinase isolated from Sinapis alba revealed the two subunits are linked by a zinc atom.

[14] When the plant experiences tissue damage, the myrosinase comes into contact with glucosinolates, quickly activating them into their potent, antibacterial form.

Another option would be to use techniques in genetic engineering to introduce the glucosinolate-myrosinase system in crops as a means of fortifying their resistance against pests.

[4] There is insufficient scientific evidence that consuming cruciferous vegetables with increased intake of isothiocyanates affects the risk of human diseases.