L-亮氨酸对人类胎盘碱性磷酸酶的抑制  

THE INHIBITION EFFECT OF L LEUCINE ON HUMAN PLACENTAL ALKALINE PHOSPHATASE

作　　者：耿芳宋[1] 王秀丽[1] 张社华[1] 李馨 

机构地区：[1]青岛医学院

出　　处：《青岛医学院学报》1998年第1期1-3,共3页Acta Academiae Medicinae Qingdao Universitatis

基　　金：山东省卫生厅科研基金

摘　　要：①目的确定Ｌ－亮氨酸（Ｌ－Ｌｅｕ）对人类胎盘碱性磷酸酶（ＰＬＡＰ）的抑制类型，并探讨其抑制机理。②方法应用分光光度法分别测定有Ｌ－Ｌｅｕ和无Ｌ－Ｌｅｕ存在下的酶活力，根据其活力变化求出酶的相对活力；用双倒数作图法，确定Ｌ－Ｌｅｕ对ＰＬＡＰ的抑制类型并求出其抑制常数（Ｋｉ）；同时也观察了ｐＨ对抑制作用的影响。③结果Ｌ－Ｌｅｕ对ＰＬＡＰ有明显地抑制作用，抑制程度与ｐＨ有关；双倒数作图得到一组平行线，Ｋｉ为１．９８ｍｍｏｌ／Ｌ．④结论Ｌ－Ｌｅｕ是ＰＬＡＰ的反竞争性抑制剂。Objective To determine the inhibition type of L leucine( L Leu) on human placental alkaline phosphatase (PLAP) and discuss the molecular mechanism underlying the inhibition activity. Methods Spectrophotometry was used to study the activity of PLAP in the presence and absence of L Leu. PLAP relative activity was calculated according to the absorbance variation. The inhibition type and inhibition constant (Ki) of L Leu on PLAP were determined by using the double reciprocal plot. The effect of pH on L Leu inhibition activity was studied. Results The activity of PLAP was obviously inhibited by L leu. A group of parallel lines was obtained by using the double reciprocal plot. The inhibition constant (Ki) was 1.98mmol/L. Conclusion L Leu is an uncompetitive inhibitor of PLAP. The ihhibition activity on PLAP was affected by the pH of solutions.

关 键 词：碱性磷酸酶类 胎盘 反竞争性抑制剂 L-亮氨酸 

分 类 号：Q556.1[生物学—生物化学]