Effects of endurance exercise on carnitine palmitoyltransferase I from rat heart, skeletal muscle and liver mitochondria

1988 ◽  
Vol 963 (3) ◽  
pp. 562-565 ◽  
Author(s):  
Manuel Guzmán ◽  
José Castro
Keyword(s):  
Skeletal Muscle ◽  
Endurance Exercise ◽  
Rat Heart ◽  
Liver Mitochondria ◽  
Carnitine Palmitoyltransferase ◽  
Carnitine Palmitoyltransferase I

scholarly journals Effects of pH on the interaction of substrates and malonyl-CoA with mitochondrial carnitine palmitoyltransferase I

1984 ◽  
Vol 219 (2) ◽  
pp. 601-608 ◽  
Author(s):  
S E Mills ◽  
D W Foster ◽  
J D McGarry
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Liver Mitochondria ◽  
Fatty Acyl ◽  
Carnitine Palmitoyltransferase ◽  
Skeletal Muscle Mitochondria ◽  
Malonyl Coa ◽  
Effects Of Ph ◽  
Carnitine Palmitoyltransferase I ◽  
Cpt I

The kinetics of carnitine palmitoyltransferase I (CPT I; EC 2.3.1.21) were examined in mitochondria from rat liver, heart and skeletal muscle as a function of pH over the range 6.8-7.6. In all three tissues raising the pH resulted in a fall in the Km for carnitine, no change in the Km for palmitoyl-CoA or Octanoyl-CoA, and a marked decrease in the inhibitory potency of malonyl-CoA. Studies with skeletal-muscle mitochondria established that increasing pH was accompanied by an increase in the Kd of the malonyl-CoA binding site for this ligand, coupled with a decrease in the Kd for fatty acyl-CoA species to compete for malonyl-CoA binding. Three principal conclusions are drawn. (1) The pH-induced shift in malonyl-CoA sensitivity of CPT I is not a phenomenon restricted to liver mitochondria. (2) At any given pH within the range tested, the ability of malonyl-CoA (and closely related compounds) to inhibit enzyme activity is governed by the efficiency of their binding to the malonyl-CoA site. (3) The competitive interaction between fatty acyl-CoA substrates and malonyl-CoA as regards CPT I activity is exerted at the malonyl-CoA binding site. Finally, the possibility is strengthened that the malonyl-CoA binding site is distinct from the active site of CPT I.

scholarly journals Observations on the affinity for carnitine, and malonyl-CoA sensitivity, of carnitine palmitoyltransferase I in animal and human tissues. Demonstration of the presence of malonyl-CoA in non-hepatic tissues of the rat

1983 ◽  
Vol 214 (1) ◽  
pp. 21-28 ◽  
Author(s):  
J D McGarry ◽  
S E Mills ◽  
C S Long ◽  
D W Foster
Keyword(s):  
Skeletal Muscle ◽  
Carnitine Palmitoyltransferase ◽  
Acid Oxidation ◽  
Long Chain Fatty Acid ◽  
Intracellular Location ◽  
Adult Rat ◽  
Malonyl Coa ◽  
Carnitine Palmitoyltransferase I ◽  
20 Nm ◽  
Carnitine Palmitoyl Transferase I

The requirement for carnitine and the malonyl-CoA sensitivity of carnitine palmitoyl-transferase I (EC 2.3.1.21) were measured in isolated mitochondria from eight tissues of animal or human origin using fixed concentrations of palmitoyl-CoA (50 microM) and albumin (147 microM). The Km for carnitine spanned a 20-fold range, rising from about 35 microM in adult rat and human foetal liver to 700 microM in dog heart. Intermediate values of increasing magnitude were found for rat heart, guinea pig liver and skeletal muscle of rat, dog and man. Conversely, the concentration of malonyl-CoA required for 50% suppression of enzyme activity fell from the region of 2-3 microM in human and rat liver to only 20 nM in tissues displaying the highest Km for carnitine. Thus, the requirement for carnitine and sensitivity to malonyl-CoA appeared to be inversely related. The Km of carnitine palmitoyltransferase I for palmitoyl-CoA was similar in tissues showing large differences in requirement for carnitine. Other experiments established that, in addition to liver, heart and skeletal muscle of fed rats contain significant quantities of malonyl-CoA and that in all three tissues the level falls with starvation. Although its intracellular location in heart and skeletal muscle is not known, the possibility is raised that malonyl-CoA (or a related compound) could, under certain circumstances, interact with carnitine palmitoyltransferase I in non-hepatic tissues and thereby exert control over long chain fatty acid oxidation.

Differential Regulation of Carnitine Palmitoyltransferase-I Gene Isoforms (CPT-I α and CPT-Iβ ) in the Rat Heart

2001 ◽  
Vol 33 (2) ◽  
pp. 317-329 ◽  
Author(s):  
George A. Cook ◽  
Timmye L. Edwards ◽  
Michelle S. Jansen ◽  
Suleiman W. Bahouth ◽  
Henry G. Wilcox ◽  
...  
Keyword(s):  
Rat Heart ◽  
Differential Regulation ◽  
Carnitine Palmitoyltransferase ◽  
Carnitine Palmitoyltransferase I ◽  
Gene Isoforms ◽  
Cpt I ◽  
I Gene

scholarly journals Restoration of the properties of carnitine palmitoyltransferase I in liver mitochondria during re-feeding of starved rats

1986 ◽  
Vol 239 (2) ◽  
pp. 485-488 ◽  
Author(s):  
B D Grantham ◽  
V A Zammit
Keyword(s):  
Liver Mitochondria ◽  
Carnitine Palmitoyltransferase ◽  
Kinetic Properties ◽  
Malonyl Coa ◽  
Carnitine Palmitoyltransferase I ◽  
Cpt I

The recovery of the parameters of the kinetic properties of carnitine palmitoyltransferase (CPT) I in liver mitochondria of starved rats was studied after re-feeding animals for various periods of time. There were no significant changes either in the activity of the enzyme at high palmitoyl-CoA concentrations or in the affinity of the enzyme for palmitoyl-CoA, or in the sensitivity of CPT I to malonyl-CoA inhibition after 3 h or 6 h re-feeding. After 24 h re-feeding, both the affinity of the enzyme for palmitoyl-CoA and the activity of the enzyme were still not significantly different from those for the enzyme in mitochondria from 24 h-starved animals. By contrast, the sensitivity of CPT I to malonyl-CoA inhibition was largely, but not fully, restored to that observed in mitochondria from fed rats.

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