AN IMPROVED ASSAY FOR PYRUVATE-DEHYDROGENASE IN LIVER AND HEART

被引:11
作者
PAXTON, R
SIEVERT, LM
机构
[1] Dept. Physiology, Auburn University, AL 36849-5520, Auburn
关键词
D O I
10.1042/bj2770547
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
A radiochemical assay was developed to measure pyruvate dehydrogenase complex (PDC) activity in liver and heart without interference by branched-chain 2-oxo acid dehydrogenase (BCODH). Decarboxylation of pyruvate by BCODH was eliminated by using low pyruvate concentration (0.5 mM), a preferred substrate for BCODH (3-methyl-2-oxopentanoate) that is not used by PDC, and a competitive inhibitor of BCODH, dichloroacetate. This method was validated by assaying a combination of both purified enzymes and tissue homogenates with known amounts of added BCODH. The actual percentage of active PDC decreased after 48 h starvation from 13.6 to 3.1 in liver and from 77.1 to 9.0 in heart. Total PDC activity (munits of PDC/units of citrate synthase) in starved rats was increased by 34% in liver and decreased by 23% in heart. Total PDC activity (munits/g wet wt.) in fed- and starved-rat liver was 0.8 and 1.3, and in heart was 6.6 and 5.8, respectively.
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页码:547 / 551
页数:5
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