THE PRIMARY STRUCTURE OF THE BACILLUS-AMYLOLIQUEFACIENS INTRACELLULAR SERINE PROTEINASE .3. AMINO-ACID-SEQUENCES OF PEPTIDES FROM THE GLU,ASP-SPECIFIED PROTEINASE HYDROLYSATE - RECONSTRUCTION OF THE INTRACELLULAR SERINE PROTEINASE PRIMARY STRUCTURE

Glu,Asp-specified protease hydrolysate of intracellular serine proteinase (ISP) was separated by ion-exchange chromatography on a sulphocationite resin followed by HPLC to yield 30 individual peptides. Their sequences, spanning to 243 amino acid residues, were determined by the manual Edman procedure. Four overlapping fragments were reconstructed by comparing their sequences with those of tryptic and chymotryptic peptides. To arrange these fragment in the proteinase polypeptide chain and to reconstruct the enzyme's total sequence, additional peptides were isolated from the tryptic hydrolysate and analysed. Primary structure of ISP, corresponding to 297 amino acid residues, was reconstructed. Its comparison with related serine proteinases revealed the following levels of homology: with Bacillus subtilis intracellular serine proteinase, 88%; with secretory subtilisin BPN' produced by B. amyloliquefaciens, 46%.