Carnitine Palmitoyltransferase I (CPT I) Activity and Its Regulation by Malonyl-CoA Are Modulated by Age and Cold Exposure in Skeletal Muscle Mitochondria from Newborn Pigs

The sensitivity of carnitine palmitoyltransferase I (CPT I; EC 2.3.1.21) to inhibition by malonyl-CoA and related compounds was examined in isolated mitochondria from liver, heart and skeletal muscle of the rat. In all three tissues the same order of inhibitory potency emerged: malonyl-CoA much greater than succinyl-CoA greater than methylmalonyl-CoA much greater than propionyl-CoA greater than acetyl-CoA. For any given agent, suppression of CPT I activity was much greater in skeletal muscle than in liver, with the heart enzyme having intermediate sensitivity. With skeletal-muscle mitochondria a high-affinity binding site for [14C]malonyl-CoA was readily demonstrable (Kd approx. 25 nM). The ability of other CoA esters to compete with [14C]malonyl-CoA for binding to the membrane paralleled their capacity to inhibit CPT I. Palmitoyl-CoA also competitively inhibited [14C]malonyl-CoA binding, in keeping with its known ability to overcome malonyl-CoA suppression of CPT I. For reasons not yet clear, free CoA displayed anomalous behaviour in that its competition for [14C]malonyl-CoA binding was disproportionately greater than its inhibition of CPT I. Three major conclusions are drawn. First, malonyl-CoA is not the only physiological compound capable of suppressing CPT I, since chemically related compounds, known to exist in cells, also share this property, particularly in tissues where the enzyme shows the greatest sensitivity to malonyl-CoA. Second, malonyl-CoA and its analogues appear to interact with the same site on the mitochondrial membrane, as may palmitoyl-CoA. Third, the degree of site occupancy by inhibitors governs the activity of CPT I.

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

Biochemical Journal ◽

10.1042/bj2190601 ◽

1984 ◽

Vol 219 (2) ◽

pp. 601-608 ◽

Cited By ~ 40

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.

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CARNITINE PALMITOYLTRANSFERASE I ACTIVITY IS UNAFFECTED BY CALCIUM AND ENERGY CHARGE METABOLITES IN HUMAN SKELETAL MUSCLE MITOCHONDRIA

Medicine & Science in Sports & Exercise ◽

10.1097/00005768-200305001-00456 ◽

2003 ◽

Vol 35 (Supplement 1) ◽

pp. S83

Author(s):

V Bezaire ◽

E Hultman ◽

G J.F. Heigenhauser ◽

L L. Spriet

Keyword(s):

Skeletal Muscle ◽

Human Skeletal Muscle ◽

Energy Charge ◽

Carnitine Palmitoyltransferase ◽

Muscle Mitochondria ◽

Skeletal Muscle Mitochondria ◽

Carnitine Palmitoyltransferase I

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Carnitine palmitoyltransferase I control of acetogenesis, the major pathway of fatty acid β-oxidation in liver of neonatal swine

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00634.2009 ◽

2010 ◽

Vol 298 (5) ◽

pp. R1435-R1443 ◽

Cited By ~ 15

Author(s):

Xi Lin ◽

Kwanseob Shim ◽

Jack Odle

Keyword(s):

Fatty Acid ◽

Ketone Bodies ◽

Carnitine Palmitoyltransferase ◽

Acid Oxidation ◽

Major Pathway ◽

Malonyl Coa ◽

Suckling Piglets ◽

Carnitine Palmitoyltransferase I ◽

Newborn Pigs ◽

Cpt I

To examine the regulation of hepatic acetogenesis in neonatal swine, carnitine palmitoyltransferase I (CPT I) activity was measured in the presence of varying palmitoyl-CoA (substrate) and malonyl-CoA (inhibitor) concentrations, and [1-14C]-palmitate oxidation was simultaneously measured. Accumulation rates of 14C-labeled acetate, ketone bodies, and citric acid cycle intermediates within the acid-soluble products were determined using radio-HPLC. Measurements were conducted in mitochondria isolated from newborn, 24-h (fed or fasted), and 5-mo-old pigs. Acetate rather than ketone bodies was the predominant radiolabeled product, and its production increased twofold with increasing fatty acid oxidation during the first 24-h suckling period. The rate of acetogenesis was directly proportional to CPT I activity. The high activity of CPT I in 24-h-suckling piglets was not attributable to an increase in CPT I gene expression, but rather to a large decrease in the sensitivity of CPT I to malonyl-CoA inhibition, which offset a developmental decrease in affinity of CPT I for palmitoyl-CoA. Specifically, the IC50 for malonyl-CoA inhibition and Km value for palmitoyl-CoA measured in 24-h-suckling pigs were 1.8- and 2.7-fold higher than measured in newborn pigs. The addition of anaplerotic carbon from malate (10 mM) significantly reduced 14C accumulation in acetate ( P < 0.003); moreover, the reduction was much greater in newborn (80%) than in 24-h-fed (72%) and 5-mo-old pigs (55%). The results demonstrate that acetate is the primary product of hepatic mitochondrial β-oxidation in Sus scrofa and that regulation during early development is mediated primarily via kinetic modulation of CPT I.

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Human skeletal muscle carnitine palmitoyltransferase I activity determined in isolated intact mitochondria

Journal of Applied Physiology ◽

10.1152/jappl.1998.85.1.148 ◽

1998 ◽

Vol 85 (1) ◽

pp. 148-153 ◽

Cited By ~ 68

Author(s):

Phanélie M. Berthon ◽

Richard A. Howlett ◽

George J. F. Heigenhauser ◽

Lawrence L. Spriet

Keyword(s):

Skeletal Muscle ◽

Citrate Synthase ◽

Vastus Lateralis ◽

Maximal Oxygen Consumption ◽

Carnitine Palmitoyltransferase ◽

Vastus Lateralis Muscle ◽

Malonyl Coa ◽

Human Muscle Biopsy ◽

Carnitine Palmitoyltransferase I ◽

Cpt I

This study was designed to compare the activity of skeletal muscle carnitine palmitoyltransferase I (CPT I) in trained and inactive men ( n = 14) and women ( n = 12). CPT I activity was measured in intact mitochondria, isolated from needle biopsy vastus lateralis muscle samples (∼60 mg). The variability of CPT I activity determined on two biopsy samples from the same leg on the same day was 4.4, whereas it was 7.0% on two biopsy samples from the same leg on different days. The method was sensitive to the CPT I inhibitor malonyl-CoA (88% inhibition) and therefore specific for CPT I activity. The mean CPT I activity for all 26 subjects was 141.1 ± 10.6 μmol ⋅ min−1 ⋅ kg wet muscle (wm)−1 and was not different when all men vs. all women (140.5 ± 15.7 and 142.2 ± 14.5 μmol ⋅ min−1 ⋅ kg wm−1, respectively) were compared. However, CPT I activity was significantly higher in trained vs. inactive subjects for both men (176.2 ± 21.1 vs. 104.1 ± 13.6 μmol ⋅ min−1 ⋅ kg wm−1) and women (167.6 ± 14.1 vs. 91.2 ± 9.5 μmol ⋅ min−1 ⋅ kg wm−1). CPT I activity was also significantly correlated with citrate synthase activity (all subjects, r = 0.76) and maximal oxygen consumption expressed in milliliters per kilogram per minute (all subjects, r = 0.69). The results of this study suggest that CPT I activity can be accurately and reliably measured in intact mitochondria isolated from human muscle biopsy samples. CPT I activity was not affected by gender, and higher activities in aerobically trained subjects appeared to be the result of increased mitochondrial content in both men and women.

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Vergleichende Untersuchungen zu ausgewählten Kriterien des Energiestoffwechsels in Skelettmuskulatur, Plasma und Lymphozyten bei gesunden und an Congenitaler Myofibrillärer Hypoplasie erkrankten Ferkeln

Archives Animal Breeding ◽

10.5194/aab-52-284-2009 ◽

2009 ◽

Vol 52 (3) ◽

pp. 284-298

Author(s):

A. Bull ◽

P. Engel ◽

V. Dzapo

Keyword(s):

Skeletal Muscle ◽

Enzyme Activity ◽

Carnitine Palmitoyltransferase ◽

Muscle Mitochondria ◽

Atp Production ◽

Healthy Siblings ◽

Carnitine Palmitoyltransferase I ◽

Cpt I ◽

Possible Cause ◽

Vergleichende Untersuchungen

Abstract. Title of the paper: Comparative investigations of selected criteria of energy metabolism in skeletal muscle, plasma and lymphocytes in healthy and in piglets with congenital myofibrillar hypoplasia Carnitine contents of skeletal muscle, plasma and lymphocytes, the capacity of ATPsynthesis in muscle mitochondria and lymphocytes, and the enzyme activity of carnitine palmitoyltransferase I (CPT I) in muscle mitochondria were determined in piglets with congenital myofibrillar hypoplasia (CMH) in comparision to their clinical healthy siblings and piglets from CMH-free litters. Tendentious differences in the relation of acylcarnitine to free carnitine in healthy piglets and piglets suffering from CMH could be detected. Healthy piglets showed in tendency superiority in the ATP-production of their lymphocytes compared with diseased animals. Depending on the applied substrate, muscle mitochondria showed tendentially differences in the ATP-production between CMH-affected and healthy litters, so that a connection between CMH and the lipid metabolism, particular the β-oxidation, is supposed. Differences in the carnitine palmitoyltransferase I-activity as a possible cause for CMH could be excluded.

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Use of a selective inhibitor of liver carnitine palmitoyltransferase I (CPT I) allows quantification of its contribution to total CPT I activity in rat heart. Evidence that the dominant cardiac CPT I isoform is identical to the skeletal muscle enzyme

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)47214-6 ◽

1994 ◽

Vol 269 (42) ◽

pp. 26443-26448 ◽

Cited By ~ 2

Author(s):

B C Weis ◽

A T Cowan ◽

N Brown ◽

D W Foster ◽

J D McGarry

Keyword(s):

Skeletal Muscle ◽

Rat Heart ◽

Selective Inhibitor ◽

Carnitine Palmitoyltransferase ◽

Muscle Enzyme ◽

Carnitine Palmitoyltransferase I ◽

Cpt I

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Cold acclimation increases carnitine palmitoyltransferase I activity in oxidative muscle of striped bass

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1994.266.2.r405 ◽

1994 ◽

Vol 266 (2) ◽

pp. R405-R412 ◽

Cited By ~ 3

Author(s):

K. J. Rodnick ◽

B. D. Sidell

Keyword(s):

Cold Acclimation ◽

Striped Bass ◽

Fatty Acyl ◽

Thermal Acclimation ◽

Carnitine Palmitoyltransferase ◽

Malonyl Coa ◽

Red Muscle ◽

Carnitine Palmitoyltransferase I ◽

Cpt I ◽

Long Chain

The effect of thermal acclimation on the activity of carnitine palmitoyltransferase I (CPT I), the rate-limiting enzyme for beta-oxidation of long-chain fatty acids, was determined in oxidative red muscle of striped bass (Morone saxatilis) acclimated at 5 or 25 degrees C. As observed in mammalian tissues, malonyl-CoA potently inhibited CPT I activity of mitochondria. Inhibition by malonyl-CoA required inclusions of both bovine serum albumin (BSA) and palmitoyl-CoA in the reaction media. Because BSA binds long-chain fatty acyl-CoAs, this observation suggests that free fatty acyl-CoAs may disrupt mitochondrial membranes and affect the CPT I protein. Cold acclimation increased citrate synthase activity 1.6-fold and total CPT activity 2-fold in homogenates of red muscle; free carnitine increased 62%, and specific activity of CPT I in mitochondria increased 2-fold. No differences were observed between cold- and warm-acclimated fish in substrate-binding properties of CPT I at an assay temperature of 15 degrees C, as judged by the Michaelis constant (Km) for carnitine (0.11 +/- 0.02 vs. 0.13 +/- 0.02 mM) or inhibition of CPT I, as determined by the half-maximal inhibition concentration (IC50) for malonyl-CoA (0.14 +/- 0.05 vs. 0.09 +/- 0.03 microM). Thermal sensitivity of CPT I (Q10 = 2.91 +/- 0.12 vs. 3.02 +/- 0.20) and preference of CPT I for different long-chain fatty acyl-CoA substrates (16:1-CoA = 16:0-CoA > 18:1-CoA) were not altered by thermal acclimation.(ABSTRACT TRUNCATED AT 250 WORDS)

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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

Biochemical Journal ◽

10.1042/bj2140021 ◽

1983 ◽

Vol 214 (1) ◽

pp. 21-28 ◽

Cited By ~ 386

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.

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Evidence that the sensitivity of carnitine palmitoyltransferase I to inhibition by malonyl-CoA is an important site of regulation of hepatic fatty acid oxidation in the fetal and newborn rabbit. Perinatal development and effects of pancreatic hormones in cultured rabbit hepatocytes

Biochemical Journal ◽

10.1042/bj2690409 ◽

1990 ◽

Vol 269 (2) ◽

pp. 409-415 ◽

Cited By ~ 46

Author(s):

C Prip-Buus ◽

J P Pegorier ◽

P H Duee ◽

C Kohl ◽

J Girard

Keyword(s):

Fatty Acid ◽

Cyclic Amp ◽

Fatty Acid Oxidation ◽

Carnitine Palmitoyltransferase ◽

Acid Oxidation ◽

Fetal Hepatocytes ◽

Malonyl Coa ◽

Carnitine Palmitoyltransferase I ◽

Cpt I ◽

Hepatic Fatty Acid Oxidation

The temporal changes in oleate oxidation, lipogenesis, malonyl-CoA concentration and sensitivity of carnitine palmitoyltransferase I (CPT 1) to malonyl-CoA inhibition were studied in isolated rabbit hepatocytes and mitochondria as a function of time after birth of the animal or time in culture after exposure to glucagon, cyclic AMP or insulin. (1) Oleate oxidation was very low during the first 6 h after birth, whereas lipogenesis rate and malonyl-CoA concentration decreased rapidly during this period to reach levels as low as those found in 24-h-old newborns that show active oleate oxidation. (2) The changes in the activity of CPT I and the IC50 (concn. causing 50% inhibition) for malonyl-CoA paralleled those of oleate oxidation. (3) In cultured fetal hepatocytes, the addition of glucagon or cyclic AMP reproduced the changes that occur spontaneously after birth. A 12 h exposure to glucagon or cyclic AMP was sufficient to inhibit lipogenesis totally and to cause a decrease in malonyl-CoA concentration, but a 24 h exposure was required to induce oleate oxidation. (4) The induction of oleate oxidation by glucagon or cyclic AMP is triggered by the fall in the malonyl-CoA sensitivity of CPT I. (5) In cultured hepatocytes from 24 h-old newborns, the addition of insulin inhibits no more than 30% of the high oleate oxidation, whereas it stimulates lipogenesis and increases malonyl-CoA concentration by 4-fold more than in fetal cells (no oleate oxidation). This poor effect of insulin on oleate oxidation seems to be due to the inability of the hormone to increase the sensitivity of CPT I sufficiently. Altogether, these results suggest that the malonyl-CoA sensitivity of CPT I is the major site of regulation during the induction of fatty acid oxidation in the fetal rabbit liver.

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