磷酸吡哆醛修饰的蛇肌果糖1,6-二磷酸酯酶的时间分辨荧光分析

Time Resolved Fluorescence Studies of Snake Muscle Fructose 1,6-Bisphosphatase Labeled with Pyridoxal 5-phosphate

在别构抑制剂AMP或底物果糖1,6-二磷酸(FruP_2)存在下,磷酸吡哆醛(PLP)分别专一性地修饰在蛇肌果糖1,6-二磷酸酯酶(FruP_2ase,E.C.3.1.3.11.)的催化部位或别构部位。测得了修饰在催化部位或别构部位的PLP的荧光寿命及其连续分布。通过荧光寿命分布宽度的比较,认为该酶的活性部位柔性大于别构部位的柔性。

The active site and allosteric site of snake muscle fructose 1,6-bisphosph-atase (FruP2ase, E.C.3.1.3.11) were labelled by reaction with pyridoxal 5-phosph-ate in the presence of allosteric inhibitor AMP or substrate FruP2, respectively.Fluorescence lifetimes of the modified enzyme were determined in terms of exponential decays and continuous distributions.The results suggest that the active site of FruP2ase is more flexible than the allosteric site.