蛇肌果糖1，6－二磷酸酯酶、果糖2，6－二磷酸、AMP的结合部位关系

腺苷－磷酸（ＡＭＰ）对４个快反应巯基被修饰的蛇肌果糖１，６－二磷酸酯酶活性的抑制作用增强，而该修饰的酶受果糖２，６－二磷酸的抑制脱敏。ＡＭＰ对酶抑制为半部位反应，酶受果糖２，６－二磷酸抑制的脱敏则表现为全部位反应。经枯草杆菌蛋白酶限制性酶解的果糖１，６－二磷酸酯酶的Ｋｉ（ＡＭＰ）增大１０倍，但受果糖２，６－二磷酸抑制的性质不变。经胰蛋白酶限制性酶解的果糖１，６－二磷酸酯酶的活性不再为ＡＭＰ抑制，但果糖２，６－二磷酸对该形式酶的抑制作用则明显增强，由于该酶失去受ＡＭＰ的抑制作用，因此ＡＭＰ促进果糖２，６－二磷酸抑制的性质亦随之丧失。据此提出在蛇肌果糖１，６－二磷酸酯酶中果糖２，６－二磷酸不是结合在ＡＭＰ结合部位上的看法。

The Relationship of the Fructose 2,6-bisphosphate and the AMP Binding Sites of Snake Muscle Fructose 1, 6-bisphosphatase

Fructose 2,6-bispphosphate and AMP are respectively competitive and noncompetitive inhibitors for snake muscle fructose 1,6-bisphosphatase(FruP2ase).When the fast reactive SH groups of the enzyme were modified,the inhibiting effect of AMP at pH7.5 was strengthened while that of Fru2,6P2 was to maximally desensitize the enzyme to inhibition.It indicated that the inhibition of AMP was a partial event while that of Fru2, 6P2 was a whole molecule effect.The K1 of AMP for the enzyme that was limitedly proteolyzed by subtilisin had a 10-fold increase but that of Fru2,6P2 remained unchanged. When FruP2ase was limitedly proteolyzed with trypsin the modified enzyme was no longer inhibited by AMP but became more strongly inhibited by Frn2,6P2.These results indicate that the binding site of AMP is separated from that of Fru2,6P2 for the snake muscle FruP2ase.