THE REGULATION OF FATTY-ACID CHAIN ELONGATION IN RAT-LIVER MICROSOMES - ROLE OF FASTING AND COASH

被引:3
作者
REICHELT, WH [1 ]
GRAV, HJ [1 ]
CHRISTIANSEN, EN [1 ]
机构
[1] UNIV OSLO,INST NUTR RES,N-0316 OSLO 3,NORWAY
来源
BIOCHIMICA ET BIOPHYSICA ACTA-LIPIDS AND LIPID METABOLISM | 1994年 / 1214卷 / 02期
关键词
FATTY ACID ELONGATION; COASH; FASTING; MICROSOME; ENZYME KINETICS; (RAT); (LIVER);
D O I
10.1016/0005-2760(94)90033-7
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 elongation system for palmitic acid in rat liver microsomes was decreased to 1/3 by fasting, while the elongation of eicosapentaenoic acid was not sensitive to fasting. The rate of eicosapentaenoic acid elongation in the fed state was 50% higher than using palmitic acid as a substrate. The saturated and polyunsaturated fatty acyl-CoA substrates exhibited positive cooperativity on the rate-limiting condensing step in the elongation system, with a Hill constant of approx. 2. An inhibition by CoASH on the total elongation reaction as well as on the condensation step was demonstrated using acyl-CoA substrates, and followed a hyperbolic pattern. The concentrations giving a 50% inhibition (30-70 mu M) were in the range found in rat hepatocyte cytosol, indicating that free CoASH has the potential to act as a physiological regulator.
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页码:109 / 114
页数:6
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