Isolation of an extracellular neutral proteinase from Pseudomonas fragi

A single proteolytic enzyme (EC 3.4.4.-) was isolated from culture supernatants of Pseudomonas fragi with 20% yielded and 60-fold purification by means of stepwise DEAE-Sephadex batch adsorption, ammonium sulfate precipitation, gel filtration and DEAE-cellulose chromatography. The enzyme was Zn-2+ activated and Ca-2+ stabilized, had optimum activity at pH 6.5--8.0 and 40 degrees C. The molecular weight range was 40 000--50 000 as determined by dodecylsulfate gel electrophoresis, gel filtration and Zn assay. This proteinase has properties similar to other extracellular bacterial neutral proteinases.