Subtilisin Carlsberg. V. The complete sequence; comparison with subtilisin BPN'; evolutionary relationships.

Evidence is presented for the complete amino acid sequence of subtilisin Carlsberg. The protein consists of a single peptide chain of 274 residues. Comparison with subtilisin BPN’ shows 84 amino acid differences and 1 additional residue in BPN’. The 84 differences can be accounted for on the basis of single or double nucleotide replacements. Within the subtilisins, there are a number of distinct repetitions of sequence; this suggests that the proteins may have evolved from shorter peptide chains by some process of extension of the sequence. The subtilisins differ in structure from other proteinases sensitive to diisopropyl fluorophosphate, as well as from proteinases of other types.