コイ肉フォスファターゼのイノシン酸分解作用におよぼすDETAの影響

概要

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The effect of EDTA was observed on the hydrolysis of IMP by an alkaline phosphatase of carp muscle. Results obtained may be summarized as follows: 1. EDTA depressed not only instantaneously the initial reaction velocity, but also time-dependantly the reaction velocity of IMP hydrolysis by the phosphatase. (Fig. 1) 2. The instantaneous effect of EDTA was apparently removed by the addition of excess Mg++. (Table 1 and Fig. 2) 3. During the preincubation of the phosphatase with EDTA, the activity, which was deter-mined after the removal of the EDTA effect by the addition of excess Mg++, was gradually de-creased. (Fig. 3) That is, the phosphatase was gradually inactivated irreversibly by EDTA. 4. The phosphatase was denatured by heat at a lower temperature in the presence of EDTA than in the absence. (Fig. 4) 5. From these results, EDTA was supposed to inhibit the phosphatase reaction by such mechanisms, that EDTA may combine instantaneously and reversibly with a metal ion which is essential to the phosphatase reaction, and the metal free phosphatase thus occurred may gradu-ally and temperature-dependantly be denatured.