TABLE 8.6 Substrate preferences of chymotrypsin Amino acid in ester Amino acid side chain kcat/KM (s-1M-1) Glycine -H 1.3×10-1 CH3 Valine -CH 2.0 CH3 Norvaline -CH,CH,CH3 3.6×102 Norleucine -CH,CH,CH.CH3 3.0×103 Phenylalanine CH2 1.0×105 Source:After A.Fersht,Structure and Mechanism in Protein Science:A Guide to Enzyme Catalysis and Protein Folding(W.H.Freeman and Company,1999),Table 7.3