Moreau H, Gargouri Y, Pieroni G, Verger R
Centre de Biochimie et de Biologie Moléculaire du CNRS, Marseille, France.
FEBS Lett. 1988 Aug 29;236(2):383-7. doi: 10.1016/0014-5793(88)80061-9.
We have shown recently that rabbit gastric lipase (RGL) purified from gastric tissue presents catalytic properties comparable with those of human gastric lipase (HGL). We report here that only one sulfhydryl group was modified per molecule of native RGL after incubation at pH 8.0 with 5,5'-dithiobis(2-nitrobenzoic acid) (NbS2) for 4 h or 4,4'-dithiopyridine (4-PDS) for 60 min. With both reagents, a direct correlation was found between the modification of one sulfhydryl group per enzyme molecule and loss of RGL activity. Incubation of RGL with the new hydrophobic sulfhydryl reagent, dodecyldithio-5-(2-nitrobenzoic acid) (C12-NbS), at 30-fold molar excess, at pH 3.0, 5.0 and 8.0, induced immediate and complete inactivation of RGL. Unlike NbS2 and 4-PDS, C12-NbS almost instantaneously stopped the course of tributyrin hydrolysis by RGL, in contrast to porcine pancreatic lipase (PPL). RGL can be included with HGL in the group of sulfhydryl enzymes.
我们最近发现，从胃组织中纯化的兔胃脂肪酶（RGL）具有与人类胃脂肪酶（HGL）相当的催化特性。我们在此报告，在pH 8.0条件下，将天然RGL与5,5'-二硫代双（2-硝基苯甲酸）（NbS2）孵育4小时或与4,4'-二硫代吡啶（4-PDS）孵育60分钟后，每分子天然RGL仅有一个巯基被修饰。使用这两种试剂时，发现每个酶分子一个巯基的修饰与RGL活性的丧失之间存在直接相关性。在pH 3.0、5.0和8.0条件下，将RGL与新的疏水性巯基试剂十二烷基二硫代-5-（2-硝基苯甲酸）（C12-NbS）以30倍摩尔过量孵育，会导致RGL立即完全失活。与NbS2和4-PDS不同，C12-NbS几乎瞬间停止了RGL对三丁酸甘油酯的水解过程，这与猪胰脂肪酶（PPL）不同。RGL可与HGL归为巯基酶类。
