[Specific features of intracellular serine proteinase of Bacillus amyloliquefaciens on native and denatured protein substrates].

The effects of intracellular serine proteinase from B. amyloliquefaciens and of extracellular subtilisin BPN' on native and denaturated protein substrates were compared. The substrate hydrolysis by the enzymes was determined by a method initiating possible participation of intracellular serine protinease in intracellular protein degradation. This approach consists in a prolonged treatment of the products obtained after proteolysis with carboxypeptidase A with a subsequent amino acid assay. It was found that intracellular serine proteinase is capable of degrading denaturated protein substrates e. g. reduced, carboxymethylated ribonuclease A and bovine serum albumin, with an efficiency comparable to that achieved by subtilisin hydrolysis. On the other hand, the intracellular enzyme attacks the native proteins much slower than substilisin.