1. Bruice, T. C., and Benkovic, S., Bioorganic Mechanisms, 1 (W. A. Benjamin, New York, 1966).
2. Bender, M. L., Kezdy, F. J., and Gunter, C. R., J. Amer. Chem. Soc., 86, 3714 (1964).
3. Bender, M. L., Chem. Rev., 60, 53 (1960).
4. Knowles, J. R., in Proc. 9th European Peptide Symposium, Paris, 1968 (in the press).
5. Knowles, J. R., and Parsons, C. A., Chem. Commun., 755 (1965).