论文部分内容阅读
生化机理关于同型胱氨酸代谢的生化途径已有广泛的研究。如图1所示,同型胱氨酸是从食物蛋氨酸中得到的,即来自动物蛋白。蛋氨酸受S-腺苷蛋氨酸合成酶(蛋氨酸活化酶)的作用,经腺苷化转为腺苷蛋氨酸。此种化合物在人体代谢中为主要甲基供体,也被认为是“活性蛋氨酸”。几乎所有甲基化反应均利用S-腺苷-蛋氨酸作为供体底物。例如,S-腺苷-蛋氨酸是合成胆硷、肌酸、N-甲基烟酰胺、肾上腺素、儿茶酚胺和甲基化核酸的甲基供体。转甲基反应的结果使S-腺苷-同型半胱氨酸形成。此种化合物对进一步的转甲基反应有
Biochemical Mechanisms Biochemical approaches to homocystine metabolism have been extensively studied. As shown in Figure 1, homocystine is derived from the food methionine, which is derived from animal protein. Methionine is activated by S-adenosylmethionine synthase (methionine-activating enzyme) and is converted to adenosylmethionine by adenylation. Such compounds are the main methyl donors in human metabolism and are also known as “active methionines.” Almost all methylation reactions use S-adenosyl-methionine as a donor substrate. For example, S-adenosyl-methionine is a methyl donor of synthetic choline, creatine, N-methylnicotinamide, epinephrine, catecholamine and methylated nucleic acids. Transmethyl reaction results in the formation of S-adenosyl-homocysteine. Such compounds for further trans methyl reaction there