摘要
从蜂毒肽作用于红细胞膜上的Na+-K+-ATPase和葡萄糖-6-磷酸脱氢酶(G-6-PD)活性变化的角度,利用分光光度法测定酶活性,研究蜂毒肽与红细胞及膜作用过程中可能的靶点,讨论了蜂毒肽溶血过程与RBC膜上2种酶活性的变化.结果发现,蜂毒肽抑制RBC膜上酶活性的主要模式为附着/插入质膜与游离态并存模式,附着/插入质膜中的作用大于游离态的作用.Na+-K+-ATPase的K+结合位点是蜂毒肽的1个作用靶点.蜂毒肽插膜过程与其对此酶的作用随时间延长同步发生.蜂毒肽通过作用于葡萄糖-6-磷酸和NADP使G-6-PD的催化受到缓慢抑制,蜂毒肽形成四聚体的程度与酶活性密切相关.EDTA抑制蜂毒肽聚集,干扰蜂毒肽作用于G-6-P,蜂毒肽作用于底物G-6-P及辅酶NADP的生化机理相似,蜂毒肽抑制作用与G-6-PD的结构无关.
The effects of melittin on the activities of Na^＋-K^＋-ATPase and glucose-6-phosphate dehydrogenase（G-6-PD） which are on the membrane of red blood cell（RBC） are chosen as the index of this study.The possible target sites of these effects through enzyme activity determination by spectrophotometry are investigated,and the hemolytic process and the activity change of these two types of enzymes on the RBC membrane are discussed.The results show that the main mode of melittin inhibition to the activity of enzymes on the RBC membrane is the coexistence of adhesion/insertion form and free-state form,and the effect of the former is more stronger than the latter.The K^＋ binding site of Na^＋-K^＋-ATPase is one of the target sites of melittin.The membrane-insertion process of melittin synchronizes with the action of melittin on this enzyme.Melittin slowly inhibits the catalysis of G-6-PD through the action on G-6-P and NADP,and the extent in which melittin forms tetramers is closely related to the enzyme activity.EDTA inhibits the aggregation of melittin,and interferes with its action on G-6-P.The biochemical mechanisms of melittin effects on the substrate G-6-P and the coenzyme NADP are similar,and the inhibition of melittin is not related to the structure of G-6-PD.
出处
《中国生物化学与分子生物学报》
CAS
CSCD
北大核心
2008年第6期522-530,共9页
Chinese Journal of Biochemistry and Molecular Biology
基金
国家自然科学基金项目(No.30770317)~~
