Zapponi M C, Ferri G, Minchiotti L, Forcina B G
Biochim Biophys Acta. 1976 Jul 19;439(1):38-46. doi: 10.1016/0005-2795(76)90157-4.
A substantial portion of the primary structure of pig liver glyceraldehyde-3-phosphate dehydrogenase has been investigated and the results compared with those previously reported for the pig muscle enzyme. Liver and muscle glyceraldehyde-3-phosphate dehydrogenases show the same amino acid content, and the first N-terminal residues occur in the same sequence. No differences in N-terminal residues and amino acid composition have been evidenced by analysis of several tryptic peptides, which account for about 50% of the total amino acid sequence. From the electrophoretic mobilities of peptides T8 T9 and T25 it is concluded that residues Asp 60, Asp 67 and Glu 220 in the reported sequence of the pig muscle enzyme must be present as amides in the liver enzyme. The NAD+ content was found to be 2 mol per tetramer, while higher values have been reported for the muscle enzyme from various mammalian sources. The reactivity of lysyl side chains towards pyridoxal 5'-phosphate has been examined: the results indicate that Lys 212 is the main site reacted in fully inactivated pig liver holoenzyme. A similar result has been found for rabbit muscle apoenzyme, whereas rabbit muscle holoenzyme reacts at Lys 212 and 191.
已对猪肝磷酸甘油醛脱氢酶一级结构的很大一部分进行了研究，并将结果与先前报道的猪肌肉酶的结果进行了比较。肝脏和肌肉中的磷酸甘油醛脱氢酶显示出相同的氨基酸含量，并且最初的N端残基序列相同。通过对几种胰蛋白酶肽的分析，未发现N端残基和氨基酸组成有差异，这些肽约占总氨基酸序列的50%。根据肽T8、T9和T25的电泳迁移率得出结论，猪肌肉酶报道序列中的天冬氨酸60、天冬氨酸67和谷氨酸220残基在肝脏酶中必须以酰胺形式存在。发现NAD+含量为每四聚体2摩尔，而来自各种哺乳动物来源的肌肉酶报道的含量更高。已研究了赖氨酰侧链对磷酸吡哆醛的反应性：结果表明，赖氨酸212是完全失活的猪肝全酶中发生反应的主要位点。兔肌肉脱辅酶也得到了类似的结果，而兔肌肉全酶在赖氨酸212和191处发生反应。
