T H E Influence of Proteins on T H E Reactivation of Yeast Invertase by Harry Wagreich, Lawrence I. Schwartz, and Henry Kamin

Saul and Nelson (1) studied the influence of proteins on the activity of yeast invertase, and found that native and denatured proteins accelerate the activity of purified invertase preparations at pH 3, but not at pH 4.5, the pH optimum of the enzyme. Herriott (2) had shown that yeast invertase inactivated by acid can be reactivated by following Anson and Mirsky's (3) procedure of allowing a solution of the inactivated enzyme to stand for varying intervals of time at pH 6. In general, Herriott was able to obtain a greater per cent reactivation using fairly crude invertase preparations. However, Saul and Nelson (1) found that only highly purified invertase preparations respond to the accelerative influence of added proteins. These authors suggest therefore, that crude preparations contain an excess of protein so that the addition of more protein seems to be without further effect. The possibility exists that there may be a relation between the reactivation of invertase preparations containing a relatively large amount of extraneous protein and the accelerative effect on the activity of highly purified preparations due to added proteins. I t is the purpose of this investigation to test this possibility by studying the effect of added proteins on the degree of reactivation of acid-inactivated yeast invertase.