Pig Muscle Carnitine Palmitoyltransferase I (CPTIβ), with LowKmfor Carnitine and Low Sensitivity to Malonyl-CoA Inhibition, Has Kinetic Characteristics Similar to Those of the Rat Liver (CPTIα) Enzyme†

The activation of overt carnitine palmitoyltransferase activity that occurs when rat liver mitochondria are incubated at near-physiological temperatures and ionic strengths was studied for mitochondria obtained from animals in different physiological states. In all instances, it was found to be due exclusively to an increase in the catalytic capacity of the enzyme and not to an increase in affinity of the enzyme for palmitoyl-CoA. The enzyme in mitochondria from fed animals always showed a larger degree of activation than that in mitochondria from starved animals. This was the case even for mitochondria (e.g. from fed diabetic animals) in which the kinetic characteristics of carnitine palmitoyltransferase were more similar to those for the enzyme in mitochondria from starved rats. Glucagon treatment of rats before isolation of the mitochondria did not affect the characteristics either of the kinetic parameters of overt carnitine palmitoyltransferase or of its activation in vitro.

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A Single Amino Acid Change (Substitution of the Conserved Glu-590 with Alanine) in the C-terminal Domain of Rat Liver Carnitine Palmitoyltransferase I Increases its Malonyl-CoA Sensitivity Close to That Observed with the Muscle Isoform of the Enzyme

Journal of Biological Chemistry ◽

10.1074/jbc.m305826200 ◽

2003 ◽

Vol 278 (36) ◽

pp. 34084-34089 ◽

Cited By ~ 14

Author(s):

Laura Napal ◽

Jia Dai ◽

Michelle Treber ◽

Diego Haro ◽

Pedro F. Marrero ◽

...

Keyword(s):

Amino Acid ◽

Rat Liver ◽

Amino Acid Change ◽

Carnitine Palmitoyltransferase ◽

Single Amino Acid ◽

Terminal Domain ◽

Malonyl Coa ◽

Single Amino Acid Change ◽

Carnitine Palmitoyltransferase I

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Deletion of the Conserved First 18 N-Terminal Amino Acid Residues in Rat Liver Carnitine Palmitoyltransferase I Abolishes Malonyl-CoA Sensitivity and Binding†

Biochemistry ◽

10.1021/bi9803426 ◽

1998 ◽

Vol 37 (31) ◽

pp. 11033-11038 ◽

Cited By ~ 32

Author(s):

Jianying Shi ◽

Hongfa Zhu ◽

Dennis N. Arvidson ◽

James M. Cregg ◽

Gebre Woldegiorgis

Keyword(s):

Amino Acid ◽

Rat Liver ◽

Carnitine Palmitoyltransferase ◽

Amino Acid Residues ◽

Terminal Amino Acid ◽

Malonyl Coa ◽

Carnitine Palmitoyltransferase I ◽

Terminal Amino

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Reconstitution of purified, active and malonyl-CoA-sensitive rat liver carnitine palmitoyltransferase I: relationship between membrane environment and malonyl-CoA sensitivity

Biochemical Journal ◽

10.1042/0264-6021:3490179 ◽

2000 ◽

Vol 349 (1) ◽

pp. 179 ◽

Cited By ~ 19

Author(s):

J. Denis MCGARRY ◽

Nicholas F. BROWN

Keyword(s):

Rat Liver ◽

Carnitine Palmitoyltransferase ◽

Malonyl Coa ◽

Carnitine Palmitoyltransferase I

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Reversible sensitization and desensitization of carnitine palmitoyltransferase I to inhibition by malonyl-CoA in isolated rat liver mitochondria. Significance for the mechanism of malonyl-CoA-induced sensitization

Biochemical Journal ◽

10.1042/bj2141027 ◽

1983 ◽

Vol 214 (3) ◽

pp. 1027-1030 ◽

Cited By ~ 13

Author(s):

V A Zammit

Keyword(s):

Rat Liver ◽

Reduced Glutathione ◽

Thiol Group ◽

Liver Mitochondria ◽

Carnitine Palmitoyltransferase ◽

Rat Liver Mitochondria ◽

Nitrobenzoic Acid ◽

Malonyl Coa ◽

Carnitine Palmitoyltransferase I ◽

Cpt I

Preincubation of rat liver mitochondria with 5,5′-dithiobis-(2-nitrobenzoic acid) (Nbs2) followed by removal of excess reagent by washing the mitochondria with 0.5 mM-reduced glutathione resulted in a desensitization of carnitine palmitoyltransferase (CPT) I activity to malonyl-CoA inhibition. The effect was not observed if mitochondria were washed with 0.5 mM-dithiothreitol. The desensitization effect of Nbs2 could be reversed by a second incubation in the presence of 8 microM-malonyl-CoA. In addition, malonyl-CoA, when present simultaneously with Nbs2, protected CPT I activity against the desensitization effect of the thiol-group reagent. These results suggest that malonyl-CoA exerts an effect on one or more thiol groups of the enzyme, and that this effect is related to the ability of the metabolite to sensitize CPT I to malonyl-CoA inhibition.

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