THE PRIMARY STRUCTURE OF CARBOXYPEPTIDASE-S1 FROM PENICILLIUM-JANTHINELLUM

The complete amino acid sequence of carboxypeptidase S1 from Penicilli um janthinellum has been determined by N-terminal sequencing of the re duced and vinylpyridinated protein and of peptides obtained by cleavag e with cyanogen bromide, iodosobenzoic acid, hydroxylamine, endoprotei nase LysC, endoproteinase AspN and Glu-specific proteinase from R lich eniformis. The enzyme consists of a single peptide chain of 433 amino acid residues and contains 9 half-cystine residues and one glycosylate d asparagine residue. A comparison to other carboxypeptidases shows th at the enzyme is homologous to carboxypeptidase-Y and carboxypeptidase -MIII from malt. Specificity and binding of substrates are discussed f rom a three-dimensional model based on the known structure of carboxyp eptidase-Y from Saccharomyces cereviciae and carboxypeptidase II from wheat.