Carnitine palmitoyltransferase activities (EC 2.3.1.–) of rat liver mitochondria
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Carnitine palmitoyltransferase activities (EC 2.3.1.-) of rat liver mitochondria.
1. A continuously recording and sensitive fluorimetric assay is described for carnitine palmitoyltransferase. This assay has been applied to whole or disintegrated mitochondria and to soluble protein fractions. 2. When rat liver mitochondria had been disintegrated by ultrasound, the specific activity of carnitine palmitoyltransferase was 15-20m-units/mg of protein. Only one-fifth of this activi...
متن کاملEffects of fasting and malonyl CoA on the kinetics of carnitine palmitoyltransferase and carnitine octanoyltransferase in intact rat liver mitochondria.
There has been considerable interest in the observation that the overt form of carnitine palmitoyltransferase (CPT1) in liver mitochondria is potently inhibited by malonyl CoA [I ,2]. It has been suggested [2] that this is a competitive type of inhibition against long chain acyl CoA substrates. However, this is based upon measurements of ketogenesis [3-51 or indirect calculations of CPT, activi...
متن کاملInteracting effects of L-carnitine and malonyl-CoA on rat liver carnitine palmitoyltransferase.
Malonyl-CoA significantly increased the Km for L-carnitine of overt carnitine palmitoyltransferase in liver mitochondria from fed rats. This effect was observed when the molar palmitoyl-CoA/albumin concentration ratio was low (0.125-1.0), but not when it was higher (2.0). In the absence of malonyl-CoA, the Km for L-carnitine increased with increasing palmitoyl-CoA/albumin ratios. Malonyl-CoA di...
متن کاملThe soluble carnitine palmitoyltransferase from bovine liver
The properties of two carnitine acyltransferases (CPT) purified from bovine liver are compared to confirm that they are different proteins. The soluble CPT and the inner CPT from mitochondria differ in subunit Mr, native Mr, pI and reactivity with thiol reagents. All eight free thiol groups in soluble CPT react with 5,5'dithiobis-(2-nitrobenzoate) in the absence of any unfolding reagent, and ac...
متن کاملBinding of 114 Clmalonyl - CoA to rat liver mitochondria after blocking of the active site of carnitine palmitoyltransferase I
1. The active site of the overt activity of carnitine palmitoyltransferase (CPT I) in rat liver mitochondria was blocked by the self-catalysed formation of the S-carboxypalmitoyl-CoA ester of (-)-carnitine, followed by washing of the mitochondria. CPT I activity in treated mitochondria was inhibited by 90-95%. 2. Binding of [14C]malonyl-CoA to these mitochondria was not inhibited as compared wi...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 1970
ISSN: 0306-3283
DOI: 10.1042/bj1190547