Studies on myrosinases. II. Purification and characterization of a myrosinase from rapeseed (Brassica napus L.)

Myrosinases (EC 3.2.3.1) are a group of isoenzymes present in Cruciferaes which catalyze the hydrolysis of glucosinolates. The myrosinases from rapeseed (Brassica napus L.) have been purified and the main component isolated and characterized. It is a glycoprotein with a molecular weight of 135 000 which consists of two peptide chains with a molecular weight of 65 000 and contains about 14% carbohydrate. It exists in 3 forms with different carbohydrate compositions and the isoelectric points are 4.96, 4.99 and 5.06, respectively. This work describes the isolation and physicochemical characterization and makes a comparison between the myrosinases from rapeseed and white mustard (Sinapis alba L.).