Galletti P, Ki Paik W, Kim S
Eur J Biochem. 1979 Jun;97(1):221-7. doi: 10.1111/j.1432-1033.1979.tb13106.x.
Membrane proteins from human erythrocytes were methylated with purified protein methylase II (S-adenosylmethionine:protein-carboxyl O-methyltransferase, EC.2.1.1.24). The methylated proteins were analyzed by dodecyl sulfate/polyacrylamide gel electrophoresis. Monomeric and dimeric glycophorin A (NaIO4/Schiff-2 and NaIO4/Schiff-1 positive bands) and 'band 4.5' were identified as two major classes of methyl-acceptor polypeptides for protein methylase II. In rabbit erythrocyte membrane where glycophorin A is absent, 'band 4.5' was the only major methyl-acceptor protein component. Extracted and purified glycophorin A from human erythrocytes was also found to be an excellent substrate for protein methylase II with a Km of 35.7 microM. The role of erythrocyte membrane protein methylation is discussed with regard to membrane function.
用人红细胞的膜蛋白与纯化的蛋白甲基化酶II（S-腺苷甲硫氨酸：蛋白质羧基O-甲基转移酶，EC.2.1.1.24）进行甲基化反应。通过十二烷基硫酸钠/聚丙烯酰胺凝胶电泳对甲基化的蛋白进行分析。单体和二聚体血型糖蛋白A（高碘酸钠/席夫2和高碘酸钠/席夫1阳性条带）以及“4.5带”被鉴定为蛋白甲基化酶II的两类主要甲基受体多肽。在缺乏血型糖蛋白A的兔红细胞膜中，“4.5带”是唯一主要的甲基受体蛋白成分。从人红细胞中提取和纯化的血型糖蛋白A也被发现是蛋白甲基化酶II的优良底物，其米氏常数为35.7微摩尔。关于膜功能，讨论了红细胞膜蛋白甲基化的作用。
