Abstract: Isolation and purification and molecular characteristic of a myrosinase,which was isolated and purified from the extraction by ammonium sulfate,DEAE-52 and Sephadex G-100 chromatography were studied.The recovery and activity of myrosinase was determined during isolation and purification.By DEAE-52 and Sephadex G-100 chromatography,an active peak was recovered.Molecular weight of the enzyme was about 105000 as assayed by gel filtration of Sephadex G-100.This enzyme exhibited one absorption maximum in the ultraviolet range at 277.3 nm.The enzyme contained free thiol.The amino acid compositions analysis indicated that high Leu and Gly content and low Cys and Lys content.

Key words: Brassica juncea Coss.Var.tumida Tsen et Lee, myrosinase, purification, properties