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Effects of diet and of alloxan-diabetes on the activity of branched-chain 2-oxo acid dehydrogenase complex and of activator protein in rat tissues.
- Source :
-
The Biochemical journal [Biochem J] 1984 Sep 15; Vol. 222 (3), pp. 711-9. - Publication Year :
- 1984
-
Abstract
- The total activities (sum of active and inactive forms) of branched-chain 2-oxo acid dehydrogenase complex in tissues of normal rats fed on a standard diet were (unit/g wet wt.): liver, 0.82; kidney, 0.77; heart, 0.57; hindlimb skeletal muscles, 0.034. Total activity was decreased in liver by 9%- or 0%-casein diets and by 48 h starvation, but not by alloxan-diabetes. Total activities were unchanged in kidney and heart. The amount of active form of the complex (in unit/g wet wt. and as % of total) in tissues of normal rats fed on standard diet was: liver, 0.45, 55%; kidney, 0.55, 71%; heart, 0.03, 5%; skeletal muscle less than 0.007, less than 20% (below lower limit of assay). The concentration of the active form of the complex was decreased in liver and kidney, but not in heart, by low-protein diets, 48 h starvation and alloxan-diabetes. In heart muscle alloxan-diabetes increased the concentration of active complex. The concentration of activator protein (which activates phosphorylated complex without dephosphorylation) in liver and kidney was decreased by 70-90% by low-protein diets and 48 h starvation. Alloxan-diabetes decreased activator protein in liver, but not in kidney. Evidence is given that in tissues of rats fed on a normal diet approx. 70% of whole-body active branched chain complex is in the liver and that the major change in activity occasioned by low-protein diets is also in the liver.
- Subjects :
- 3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)
Animals
Cell Fractionation
Diet
Enzyme Activation drug effects
Fluorides pharmacology
In Vitro Techniques
Keto Acids pharmacology
Male
Mitochondria enzymology
Mitochondria, Liver enzymology
Rats
Rats, Inbred Strains
Tissue Distribution
Diabetes Mellitus, Experimental enzymology
Ketone Oxidoreductases metabolism
Multienzyme Complexes metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0264-6021
- Volume :
- 222
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The Biochemical journal
- Publication Type :
- Academic Journal
- Accession number :
- 6487271
- Full Text :
- https://doi.org/10.1042/bj2220711