Specific labeling of the active site of cytosolic aspartate aminotransferase through the use of a cofactor analogue, N-(Bromoacetyl)pyridoxamine.
Specific labeling of the active site of cytosolic aspartate aminotransferase through the use of a cofactor analogue, N-(Bromoacetyl)pyridoxamine.
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通过使用辅因子类似物 N-(溴乙酰基)吡哆胺对胞质天冬氨酸转氨酶的活性位点进行特异性标记。
DOI：
10.1021/bi00274a006
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发表时间：
1983
期刊：
影响因子：
2.9
通讯作者：
Martinez-Carrion,M
中科院分区：
文献类型：
--
作者：
FarachJr,HA;MattinglyJr,JR;Martinez-Carrion,M
摘要：辅因子类似物N-(Bromoacty 1)吡哆胺(BAPM)用于灭活天冬氨酸氨基转移酶胞质同工酶。失活是通过活性部位赖氨基残基在(溴乙酰)-吡哆胺-转移酶复合体中形成共价键的结果。这种失活的化学计量比是转氨酶二聚体的每个亚单位含有一个(溴乙酰基)吡哆胺分子。微量的无机磷可以保护酶不被BAPM灭活。在没有磷酸盐的情况下，失活需要时间。天冬氨酸转氨酶(EC 2.6.1.1)是一种功能性二聚体，每个亚单位活化位含有1摩尔的吡哆醛5‘-磷酸结合。它通过两个半反应催化以下转化：谷氨酸+乙氧基吡哆醛。5、.P^-酮戊二酸+乙氧嘧啶。5-。P(1)
Horacio A. Farach, Jr., Joseph R. Mattingly, Jr., and Marino Martinez-Carrion* abstract: The cofactor analogue N-(bromoacety 1) pyridoxamine (BAPM) has been employed to inactivate the cytosolic isozyme of apo-aspartate aminotransferase. Inactivation is the result of covalent bond formation in the (bromoacetyl)-pyridoxamine-transferase complex, via the e-amino group of a lysyl residue at the active site. The stoichiometry of this inactivation is one molecule of (bromoacetyl) pyridoxamine per subunit of the transaminase dimer. Trace amounts of inor-ganic phosphate protect the enzyme from BAPM inactivation. In the absence of phosphate, inactivation demonstrates time,.^^. spartate aminotransferase (EC 2.6. 1.1) is a functional dimer containing 1 mol of pyridoxal 5'-phosphate bound per subunit activesite. It catalyzes the following conversion via two half-reactions: glutamate+ Epyridoxal. 5,. P^-ketoglutarate+ Epyridoxamine. 5-. P (1)