Amino acid sequence of proteinase K from the mold <i>Tritirachium album</i> Limber

Abstract

The amino acid sequence of proteinase K (EC 3.4.21.14) from Tritirachium album Limber has been determined by analysis of fragments generated by cleavage with CNBr or BNPS‐skatole. The enzyme consists of a single peptide chain containing 277 amino acid residues, corresponding to M r 28 930. Comparison of the sequence with those of the serine proteinases reveals a high degree of homology (about 35%) to the subtilisin‐related enzyme. But in contrast to the subtilisins, proteinase K contains 2 disulfide bonds and a free cysteine residue. This finding may indicate that proteinase K is a member of a new subfamily of the subtilisins.