[Carboxylic proteinase from the basidiomycete Russula decolorans Fr 0456]

A carboxylic proteinase has been isolated from a cultural filtrate of the basidiomycet Russula decolorans Fr 0456. A sequential chromatography on biospecific adsorbents containing polypeptide antibiotics gramicidin S and bacitracin used as ligands resulted in a 186-fold purification and 48% yield of the enzyme. The molecular weight of the enzyme is 35 000, pH-optimum of hemoglobin hydrolysis is 2,2, the isoelectric point lies at 4,9. The enzyme revealed a pronounced milk-clotting activity and is completely inactivated by the specific inhibitors of carboxylic proteinases--N-diazo-acetyl-N'-2,4-dinitrophenylethylenediamine and pepstatin. Its amino acid composition was also found to be similar to that of the carboxylic proteinases isolated from microscopic fungi. The data obtained suggest that the carboxylic proteinase from the basidiomycet Russula decolorans Fr 0456 is closely related to pepsin-like carboxylic proteinases, particularly to those produced by microscopic fungi.