Thioglucoside glucohydrolase (Myrosinase) (MYR)

Thioglucoside glucohydrolase, commonly known as myrosinase, is a specialized family of enzymes primarily found in cruciferous vegetables like broccoli, mustard, and cabbage, as well as in certain gut microbiota. It is the only known enzyme in nature capable of cleaving the thio-linked glucose bonds found in glucosinolates, a process that serves as a chemical defense mechanism in plants known as the "mustard oil bomb." In the context of human health and pharmacology, myrosinase is a critical therapeutic target because it converts inert dietary precursors like glucoraphanin into highly bioactive isothiocyanates, such as sulforaphane. These resulting compounds are potent chemopreventive agents that exert anti-cancer and anti-inflammatory effects by inducing Phase II detoxification enzymes via the Nrf2 pathway and modulating epigenetic markers through HDAC inhibition. Although not endogenously produced by human cells, myrosinase is utilized in enzyme-prodrug therapies and functional food development to maximize the bioavailability of health-promoting metabolites. Its activity is highly dependent on environmental factors such as pH and the presence of cofactors like ascorbic acid, which can significantly influence the ratio of beneficial isothiocyanates to potentially toxic nitriles produced during hydrolysis.

Other names

SinigrinaseSinigraseThioglucosidaseGlucosinolasebeta-thioglucosidaseGlucosinolate glucohydrolase

Myrosinase catalyzes the hydrolysis of the thioglucosidic bond in glucosinolates to produce glucose and an unstable aglycone, which spontaneously rearranges into bioactive isothiocyanates that activate the Nrf2 antioxidant pathway and inhibit histone deacetylases (HDACs).