Purification, Crystallization, and Properties of Bovine Milk Catalase

Abstract

Catalase of bovine milk was crystallized following n-butanol extraction, ammonium sulfate fractionation, ethanol-chloroform fractionation, diethyl-aminoethyl-Sephacel column chromatography, and Sephacryl S-300 gel filtration. About 120 mg crystalline catalase was produced from 1200 kg milk. The product was approximately 23,000 times as pure as milk. The crystalline catalase appeared homogeneous on disc-electrophoretic analysis. Its molecular weight was approximately 225,000 by Sephadex G-200 gel filtration. Optimum pH and temperature of the crystalline catalase were pH 8.0 and 20 °C. The enzyme had a thermostable range below 40 ° C. Its absorption spectrum showed two bands, one at 275 nm (protein) and the other from 360 to 450 nm (Soret band, heme group). About 8% sodium chloride concentration reduced catalase activity by more than 6%. © 1983, American Dairy Science Association. All rights reserved.