Pronase (Molecular Biology)

The K-1 strain of Streptomyces griseus synthesizes and secretes a mixture of proteinases that for many years has been commercially available under the proprietary name of "Pronase." Initially offered as a purified proteinase of broad specificity and widely adopted for this purpose, it became clear that pronase is composed of a variety of exo- and endopeptidases (1), thus accounting for its remarkable ability to catalyze the hydrolysis of many types of peptide bonds. Among the different constituents are more than a dozen separate enzymes having the specificities of trypsin, chymotrypsin, elastase, subtilisin, carboxypeptidase, and aminopeptidase . Many of these have been isolated in pure form, starting with the crude mixture, and subsequently characterized both structurally and kinetically. The commercial product is still referred to as "an unusually nonspecific proteinase," although it is now well known to be a mixture of proteinases. It is free of nuclease activity and hence is convenient for removing proteins in the course of procedures for the isolation of nucleic acids.