Visser S, Van Rooijen P J, Schattenkerk C, Kerling K E
Biochim Biophys Acta. 1977 Mar 15;481(1):171-6. doi: 10.1016/0005-2744(77)90148-6.
Kinetic parameters have been determined for the reaction between chymosin (EC 3.4.23.4) and synthetic peptide analogues of the sequence Leu-Ser-Phe-Met-Ala-Ile around the chymosin-sensitive Phe(105)-Met(106) bond of bovine kappa-casein. From the present and earlier results it is concluded that a minimum length of the molecular backbone with three amino acid units on both sides of the scissile bond is required to make the peptide a good substrate for the enzyme. In addition, hydrophobic side chains in the positions 103 and 108, and particularly the hydroxyl group of Ser-104 contribute to the effectiveness of the enzyme-substrate interactions. The substrate properties are markedly influenced by changes in the steric and/or polar character of the amino acid side chains in the positions 105 and 106.
