POSSIBLE REGULATION OF PYRUVATE-CARBOXYLASE FROM THIOBACILLUS-NOVELLUS BY HYDROXYPYRUVATE
POSSIBLE REGULATION OF PYRUVATE-CARBOXYLASE FROM THIOBACILLUS-NOVELLUS BY HYDROXYPYRUVATE
复制标题
DOI：
10.1007/bf01577139
复制
发表时间：
1984-01-01
影响因子：
2.6
通讯作者：
SCHARER, JM
中科院分区：
文献类型：
--
作者：
CHARLES, AM;WILLER, DW;SCHARER, JM
天冬氨酸、谷氨酸或二元酸不抑制高纯度但不均一的小米曲霉丙酮酸羧化酶的活性。唯一有效的抑制剂是反应的最终产物，其次是羟基丙酮酸。Lineweaver-Burk图显示，它对乙酰辅酶A是非竞争性的，KII为3.6 mM，而对碳酸氢镁、三磷酸腺苷和丙酮酸是非竞争性的，其KII值分别为7.1、5.5和6.47 nM。相应的KI值分别为7.02、5.4和4.25 mM。
Aspartate, glutamate or dicarboxylic acids did not inhibit the activity of a highly purified but not homogeneous preparation of pyruvate carboxylase from T. novellus. The only effective inhibitors were end-products of the reaction and, to a lesser degree, hydroxypyruvate. The latter has not been shown previously to regulate the enzyme''s activity. Lineweaver-Burk plots revealed that it was uncompetitive with respect to acetyl CoA and with a Kii of 3.6 mM, and noncompetitive with respect to bicarbonate, Mg ATP and pyruvate with respective Kii values of 7.1, 5.5 and 6.47 nM. The corresponding Kis values were 7.02, 5.4 and 4.25 mM. A mathematical model is presented that supports the findings.