Abstract
Ultraviolet irradiation of carboxypepti-dase A has been extensively investigated. In M sodium chloride solution of pH 7.5 con-taining a small amount of Brij 35, a non-ionic detergent, apparently first order inactivation was observed. No significant cleavage of peptide bonds nor large conformation change was observed.
A possible relationship between inactiva-tion of the enzyme and loss of the tryptophyl and/or tyrosyl groups has been found; for instance, 70% inactivation corresponds to the loss of each approximately one mole of these two groups. The results were discussed in respect to the nature of inactivation by ultra-violet ray.
The authors wish to express their appreciation to Prof. T. Ando and Dr. S. Horiuchi of the Faculty of Science, University of Tokyo, for making accessi-ble to them the amino acid analyzer and the date about the amino acid analysis reported here.
