Extracellular proteinase from Brevibacterium linens. Purification and characterization

Abstract

Brevibacterium linens produces proteolytic enzymes in cultivation broth. One of them was purified by application of a two step procedure involving ultrafiltration and molecular sieving. The isolated enzyme hydrolyzed natural substrates: casein, hemoglobin, ovalbumin and bovine serum albumin with rations 22.2, 3.5, 1.6, 1.2 nkat mg-1, respectively. For casein the apparent Km 1.8 mg ml-1 was determined. The proteinase is fairly stable at pH 8.0 at 30 °C. Short term incubation at 50 °C denaturated the proteinase. SDS PAGE revealed an Mr of the proteolytic enzyme about 52 000 to 55 000.