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蛇肌果糖1.6-二磷酸酯酶被枯草杆菌蛋白酶或胰蛋白酶限制性酶解,可分别产生29000和7000或32000和4000的肽段。酶解产物在pH7.5和pH9.2分别有2倍和4—5倍的激活,pH7.5的激活作用,仅可用无机磷测活法观察到。5′AMP对该产物的别构抑制作用部分或全部丧失。本文与文献[1]的结果使我们提出了天然状态的蛇肌酶的催化部位的结构是不完善的看法。被限制性酶解的蛇肌酶受6-磷酸果糖激活,同时又受6-磷酸葡萄糖酸,6-磷酸葡萄糖和还原型辅酶Ⅱ的抑制。因此限制性酶解作用可能在蛇肌中有一定生理功能。
Snake muscle fructose 1.6-diphosphatase was subtilisin or trypsin restriction enzyme digestion, resulting in peptides of 29000 and 7000 or 32000 and 4000, respectively. At pH7.5 and pH9.2, the enzymatic hydrolysis products were activated by 2-fold, 4-5-fold and pH7.5, respectively, and were only observed by inorganic phosphorus assay. Allosteric inhibition of this product is partially or completely lost by 5’AMP. The results of this paper and the literature [1] led us to suggest that the structure of the catalytic site of the natural state of snake muscle enzymes is imperfect. Restricted enzymatic snake muscle enzymes are activated by 6-phosphofructose and are simultaneously inhibited by 6-phosphogluconate, 6-phosphoglucose and reduced coenzyme II. Therefore, limiting enzymatic hydrolysis may have certain physiological functions in the snake muscle.