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Longer-term regulation of branched-chain-2-oxoacid dehydrogenase complex studied in rat hepatocytes in culture
- Source :
- Biochemical Journal; January 1989, Vol. 257 Issue: 1 p271-275, 5p
- Publication Year :
- 1989
-
Abstract
- The effect of protein-free diet to decrease liver activity of branched-chain (-2-oxoacid) dehydrogenase (BCD) complex (active form) and increase BCD kinase activity was unaffected by preparation of hepatocytes, but partially reversed by 25 h of culture of hepatocytes in medium 199. Activation of BCD complex preceded loss of BCD kinase. The effect of culture on BCD complex was completely prevented by omission of branched-chain amino acids and partially prevented by 1 mM-alpha-cyano-4-hydroxycinnamate or 0.2 mM-pyruvate/2 mM-lactate. Protein-free diet decreased plasma branched-chain amino and oxo (‘keto’) acids and increased plasma pyruvate and lactate. It is concluded: (1) that branched-chain amino acids are involved directly in regulation of activities of BCD complex and BCD kinase; (2) that mitochondrial uptake of branched-chain oxo acids is necessary for regulation of BCD complex activity; and (3) that the stable increase in BCD kinase may function as a hysteresis mechanism.
Details
- Language :
- English
- ISSN :
- 02646021 and 14708728
- Volume :
- 257
- Issue :
- 1
- Database :
- Supplemental Index
- Journal :
- Biochemical Journal
- Publication Type :
- Periodical
- Accession number :
- ejs51302459
- Full Text :
- https://doi.org/10.1042/bj2570271