Abstract
An extracellular proteinase of Pseudomonas sp. (strain L-1), one of the lytic factor against the cells of Vibrio anguillarum, was purified from the culture supernatant by ammonium sulfate fractionation, followed by a combination of column chromatography with P-cellulose and Sephadex G-100.
The molecular weight of the enzyme was estimated to be about 51, 000 by the gel filtration method.
The proteinase showed maximal activity toward casein at pH8.5 and 42-47°C. The enzyme was relatively unstable to heat, and was inactivated when heated at 50°C for 10 min.
The enzyme activity was significantly inhibited by metal chelating reagents, such as ethylenediaminetetraacetic acid and o-phenanthroline.
The sites of cleavage in the oxidized insulin B-chain with the enzyme from strain L-1 were similar to those with other alkaline proteinases from microorganisms.
From the results obtained, the proteinase from strain L-1 were presumably classified as an alkaline metalloproteinase.
