Purification of O-acetyl-lserine sulfhydrylase from lens culinaris by affinity chromatography

Abstract EN

O-acetyl-Lserine sulfhydrylase (OASSase) isolated from Lens culinaris was purified (spec.

act.

387 units/mg) to homogeniety using affinity chromatography as a major pu- rificatin step.

The enzyme, Mr = 86,000, consists of two identical subunits, has a pH optimum of 6.4 and is stable to heating up to 50°C.

This enzyme was able in vitro to catalyze the reaction of azide and O-acetylserine to form a mutagenic product on S.

tv phimurium.

Results obtained from double diffusion analysis indicated that the antibody raised against the affinity purified enzyme is monospecific, D-cycloserine, semicrabiazide and hydroxylamine are effective inhibitors of OAS¬Sase activity which is completely inhibited by iodoacetic acid.