磷酸盐对人胎盘碱性磷酸酶胍变性的影响  

EFFECT OF PHOSPHATE ON GUANIDINE DENATURATION OF HUMAN PLACENTAL ALKALINE PHOSPHATASE

作　　者：李馨[1] 

机构地区：[1]青岛大学医学院生物化学与分子生物学教研室,山东青岛266021

出　　处：《青岛大学医学院学报》2004年第2期158-159,共2页Acta Academiae Medicinae Qingdao Universitatis

摘　　要：①目的　观察磷酸盐对人胎盘碱性磷酸酶 (HPAP)胍变性的影响 ,为酶活性部位的柔性理论提供证据。②方法　应用分光光度法测定有磷酸盐及无磷酸盐存在时 ,HPAP在胍变性过程中的活力变化。③结果　低浓度的盐酸胍 (<0 .5mol/L)使变性平衡态酶活力增强 ,在有磷酸盐存在时 ,酶活力增加的更为明显 ;随着盐酸胍浓度的增加 ,酶逐渐失活 ;当盐酸胍浓度 >2 .0mol/L时 ,酶活力迅速下降 ;当盐酸胍浓度为 3.0mol/L时 ,酶活力完全丧失。但有磷酸盐存在时 ,盐酸胍浓度达到 5 .0mol/L时 ,酶活力才完全丧失。④结论　磷酸盐对HPAP胍变性有保护作用 。Objective To study the effects of phosphate on guanidine denaturation of human placental alkaline phosphatase(HPAP) and provide a theoretical basis for flexibility hypothesis of enzyme active sites. Methods Spectrophotometry was used to determine the changes of activity of HPAP during guanidine denaturation in the presence and absence of phosphate. Results The guanidine of low concentration (<0.5 mol/L) increased the activity of HPAP in the denaturation-equilibrated state, even markedly with the presence of phosphate. The enzyme was gradually inactivated with the increase of the guanidine concentrations, and rapidly decreased when the guanidine concentration reached 2.0 mol/L. The enzyme was completely inactivated at 3.0 mol/L , but, in the presence of phosphate, the enzyme lost its activity at 5.0 mol/L of guanidine. Conclusion Phosphate is effective for the protection of guanidine denaturation of HPAP, which shows that phosphate decreases the flexibility of enzyme active sites.

关 键 词：磷酸盐类 碱性磷酸酶 胎盘 变性 胍 

分 类 号：R341[医药卫生—基础医学]