Department of Biochemistry, Jozef Stefan Institute, Ljubljana, Yugoslavia.
The complete amino acid sequence of bovine spleen cathepsin S has been determined. The single-chain protein contains 217 residues and has a Mr of 23,682. The primary structure was determined by sequencing of native protein and the peptides obtained by proteolytic cleavage with beta-trypsin, papaya proteinase IV and by chemical cleavage with cyanogen bromide. Comparison of the amino terminal sequences of the heavy and the light chain of bovine cathepsin L with that of bovine cathepsin S clearly indicates that the enzymes are structurally different.