Department of Botany, University of California, Davis, California 95616.
Plant Physiol. 1982 Feb;69(2):421-3. doi: 10.1104/pp.69.2.421.
High pressure liquid chromatography was used to demonstrate that chelation of Mg(2+) into protoporphyrin IX precedes methylation in isolated greening etioplasts from cucumber (Cucumis sativus L. var. Beit Alpha) cotyledons. Mg-protoporphyrin IX synthesized in vitro from protoporphyrin IX, Mg(2+), and ATP or exogenous Mg-protoporphyrin IX could serve as substrates for the methylation step. In either case, S-adenosylmethionine was the methyl donor and could not be replaced by ATP plus methionine.
高效液相色谱法表明,在黄瓜(Cucumis sativus L. var. Beit Alpha)子叶的绿体中,镁螯合原卟啉 IX 先于甲基化。体外从原卟啉 IX、Mg2+和 ATP 或外源 Mg-原卟啉 IX 合成的 Mg-原卟啉 IX 可作为甲基化步骤的底物。在任何一种情况下,S-腺苷甲硫氨酸都是甲基供体,不能被 ATP 和蛋氨酸取代。