巯基化合物和磷酸盐及其类似物对鲍鱼碱性磷酸酶的抑制作用

Inhibitory Effects of Mercapto Compounds,Phosphate and It's Analogues on Alkaline Phosphatase from Haliotis diversicolor

研究二巯基苏糖醇(DTT)、巯基乙醇(ME)等巯基化合物及磷酸盐(Na2HPO4)、砷酸盐(Na2HAsO4)、酸盐(Na3WO4)和钼酸盐(Na3MoO4)对鲍鱼碱性磷酸酶(ALP)活力的影响.结果表明:这些效应物对该酶都具有明显的抑制作用,而且它们的抑制作用强度依次为:DTT>ME;Na2HPO4>Na3WO4>Na2HAsO4>Na3MoO4.进一步研究这些效应物对该酶的抑制作用机理,表明:巯基化合(DTT、ME)均非竞争性抑制;Na2HPO4、Na2HAsO4和Na2HWO4表现为竞争性抑制;本文测定了它们的抑制常数并加于比较.

An alkaline phosphatase(ALP,EC3.1.3.1)was purified from Haliotis diversicolor.The inhibitory effects of mercapto-compounds,phosphate and it's analogues on the enzyme activity have been studied and their inhibition types and inhibition constants have been determined.The results showed that the inhibitory effect of dithiothreitol on the enzyme was much intensive than the effect by mercaptoethanol.The values of IC_(50),inhibitor concentration leading to 50% activity lost,for dithiothreitol and mercaptoethanol were determined to be 0.36 and 23.36 mmol/L,respectively.Their inhibition on the enzyme were classified as non-competitive type,and their inhibition constants were determined to be 0.35 and 3.36 mmol/L.The inhibitory effects of phosphate(Na_2HPO_4)and it's analogues(Na_2HAsO_4,Na_3WO_4,Na_3MoO_4)on the enzyme were also investigated and compared.The results showed that the inhibition strength followed the order:Na_2HPO_4>Na_2HAsO_4>Na_3WO_4>Na_3MoO_4.When the concentration of these effects reached to 10.0 mmol/L,the enzyme activity was descended by 81%、72%、69% and 18%,respectively.