Abstract
1. A number of the peptides Glyn-L-Tyr in which n are 1, 2, 3, 4 and 5 have been synthesized and tested as substrates for carboxypeptidase.
2. By the use of Gly2-L-Tyr, the pH optimum of hydrolysis was found to be near 8.5. For comparison, the pH optimum for CbzGly-L-Tyr was checked and found to be near 7.6.
3. The values of proteolytic coefficients at the initial substrate con-centrations of 0.025M, 0.015M, 0.01M and 0.005M, and Cmax, determined at 30° and in Tris buffer at pH 8.5, were taken as measures of the relative susceptibility of hydrolysis of the substrates by carboxypeptidase. Chroma-tographic analysis of the reaction mixture proved the simple hydrolysis of the substrates to L-tyrosine and corresponding polyglycine Glya (n=1_??_5).
4. The same hydrolytic rates by carboxypeptidase of the substrates Glyn-L-Tyr (n=2_??_5) were observed; the Cmax of the substrates were 16_??_17. Gly-L-Tyr was hydrolyzed approximately 1/200 times slowly than Glyn-L-Tyr (n=2_??_5).
The authors wish to thank Prof. S. Shibuya for his interest, and Dr. A. Tanaka for his discussion in this study.
