磷脂酰乙醇胺N-甲基化对心脏肌膜囊泡中钠钙交换的抑制作用。

Inhibition of Na+-Ca2+ exchange in heart sarcolemmal vesicles by phosphatidylethanolamine N-methylation.

作者信息

Panagia V, Makino N, Ganguly P K, Dhalla N S

出版信息

Eur J Biochem. 1987 Aug 3;166(3):597-603. doi: 10.1111/j.1432-1033.1987.tb13555.x.

DOI:10.1111/j.1432-1033.1987.tb13555.x

Abstract

The effect of phosphatidylethanolamine N-methylation on Na+-Ca2+ exchange was studied in sarcolemmal vesicles isolated from rat heart. Phosphatidylethanolamine N-methylation following incubation of membranes with S-adenosyl-L-methionine, a methyl donor for the enzymatic N-methylation, inhibited Nai+-dependent Ca2+ uptake by about 50%. The N-methylation reaction did not alter the passive permeability of the sarcolemmal vesicles to Na+ and Ca2+ and did not modify the electrogenic characteristics of the exchanger. The depressant effect of phosphatidylethanolamine N-methylation on Nai+-dependent Ca2+ uptake was prevented by S-adenosyl-L-homocysteine, an inhibitor of the N-methylation. Pretreatment of sarcolemma with methyl acetimidate hydrochloride, an amino-group-blocking agent, also prevented methylation-induced inhibition of Ca2+ uptake. In the presence of exogenous phospholipid substrate, the phospholipid N-methylation process in methyl-acetimidate-treated sarcolemmal vesicles was restored and the inhibitory effect on Ca2+ uptake was evident. These results suggest that phosphatidylethanolamine N-methylation influences the heart sarcolemmal Na+-Ca2+ exchange system.

摘要

在从大鼠心脏分离的肌膜囊泡中研究了磷脂酰乙醇胺N-甲基化对Na⁺-Ca²⁺交换的影响。用S-腺苷-L-甲硫氨酸（一种用于酶促N-甲基化的甲基供体）孵育膜后进行的磷脂酰乙醇胺N-甲基化，使依赖Na⁺的Ca²⁺摄取减少了约50%。N-甲基化反应未改变肌膜囊泡对Na⁺和Ca²⁺的被动通透性，也未改变交换体的生电特性。N-甲基化抑制剂S-腺苷-L-高半胱氨酸可防止磷脂酰乙醇胺N-甲基化对依赖Na⁺的Ca²⁺摄取的抑制作用。用氨基阻断剂盐酸甲基乙脒预处理肌膜，也可防止甲基化诱导的Ca²⁺摄取抑制。在外源磷脂底物存在的情况下，经甲基乙脒处理的肌膜囊泡中的磷脂N-甲基化过程得以恢复，对Ca²⁺摄取的抑制作用明显。这些结果表明，磷脂酰乙醇胺N-甲基化影响心脏肌膜Na⁺-Ca²⁺交换系统。