KINETIC MECHANISM OF THE CYTOSOLIC MALIC ENZYME FROM HUMAN BREAST-CANCER CELL-LINE

被引：26

作者：

CHANG, GG ^{[1
]}

HUANG, TM ^{[1
]}

WANG, JK ^{[1
]}

LEE, HJ ^{[1
]}

CHOU, WY ^{[1
]}

MENG, CL ^{[1
]}

机构：

[1] NATL DEF MED CTR, DEPT DENT, TAIPEI, TAIWAN

来源：

ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS | 1992年 / 296卷 / 02期

关键词：

D O I：

10.1016/0003-9861(92)90599-R

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The kinetic mechanism of the cytosolic NADP+-dependent malic enzyme from cultured human breast cancer cell line was studied by steady-state kinetics. In the direction of oxidative decarboxylation, the initial-velocity and product-inhibition studies indicate that the enzyme reaction follows a sequential ordered Bi-Ter kinetic mechanism with NADP+ as the leading substrate followed by l-malate. The products are released in the order of CO2, pyruvate, and NADPH. The enzyme is unstable at high salt concentration and elevated temperature. However, it is stable for at least 20 min under the assay conditions. Tartronate (2-hydroxymalonate) was found to be a noncompetitive inhibitor for the enzyme with respect to l-malate. The kinetic mechanism of the cytosolic tumor malic enzyme is similar to that for the pigeon liver cytosolic malic enzyme but different from those for the mitochondrial enzyme from various sources. © 1992.

引用

页码：468 / 473

页数：6

共 26 条

[1]

BRADFORD MM, 1976, ANAL BIOCHEM, V72, P248, DOI 10.1016/0003-2697(76)90527-3

[2] SUBSTRATE AND METAL-ION INTERACTIONS IN THE NAD+ MALIC ENZYME FROM CAULIFLOWER [J].