Abstract
Carnitine palmitoyltransferase (CPT) is a mitochondrial-inner-membrane enzyme, with activities located on both the outer and inner sides of the membrane. The inhibition of CPT by bromopalmitate derivatives was studied in intact hepatic mitochondria (representing CPT-A activity, the outer enzyme), in inverted submitochondrial vesicles (representing CPT-B, the inner enzyme), and in purified hepatic CPT. Bromopalmitoyl-CoA had an I50 (concentration giving 50% inhibition of CPT activity) of 0.63 +/- 0.08 microM in intact mitochondria and 2.44 +/- 0.86 microM in inverted vesicles. Preincubation of mitochondria with bromopalmitoyl-CoA decreased V max. for both CPT-A and CPT-B. Sonication decreased sensitivity to bromopalmitoyl-CoA, and solubilization with Triton abolished sensitivity at the concentrations used (0-10 microM). Purified CPT had a bromopalmitoyl-CoA I50 of 353 microM in aqueous buffer, 67 microM in 20% dimethyl sulphoxide, 45 microM in phosphatidylcholine liposomes and 26 microM in cardiolipin liposomes. Increasing [carnitine] at constant bromopalmitoyl-CoA concentrations or increasing [bromopalmitoyl-CoA] in the preincubation resulted in increased inhibition of purified CPT. 2-Tetradecylglycidyl-CoA and malonyl-CoA did not offer measurable protection against bromopalmitoyl-CoA inhibition of the purified CPT, suggesting a different site of interaction of bromopalmitoyl-CoA with CPT. The data suggest that the sensitivity of CPT to bromopalmitoyl-CoA may be modulated by membrane environment and assay conditions.
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- Bieber L. L., Abraham T., Helmrath T. A rapid spectrophotometric assay for carnitine palmitoyltransferase. Anal Biochem. 1972 Dec;50(2):509–518. doi: 10.1016/0003-2697(72)90061-9. [DOI] [PubMed] [Google Scholar]
- Bieber L. L., Fiol C. J. Characterization and properties of carnitine acyltransferases. Biochem Soc Trans. 1986 Aug;14(4):674–676. doi: 10.1042/bst0140674. [DOI] [PubMed] [Google Scholar]
- Bird M. I., Saggerson E. D. Binding of malonyl-CoA to isolated mitochondria. Evidence for high- and low-affinity sites in liver and heart and relationship to inhibition of carnitine palmitoyltransferase activity. Biochem J. 1984 Sep 15;222(3):639–647. doi: 10.1042/bj2220639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
- Brady L. J., Silverstein L. J., Hoppel C. L., Brady P. S. Hepatic mitochondrial inner membrane properties and carnitine palmitoyltransferase A and B. Effect of diabetes and starvation. Biochem J. 1985 Dec 1;232(2):445–450. doi: 10.1042/bj2320445. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brady P. S., Brady L. J. Action in vivo and in vitro of 2-tetradecylglycidic acid, 2-tetradecylglycidyl-CoA and 2-tetradecylglycidylcarnitine on hepatic carnitine palmitoyltransferase. Biochem J. 1986 Sep 15;238(3):801–809. doi: 10.1042/bj2380801. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brendel K., Bressler R. The resolution of (plus or minus)-carnitine and the synthesis of acylcarnitines. Biochim Biophys Acta. 1967 Feb 14;137(1):98–106. doi: 10.1016/0005-2760(67)90012-4. [DOI] [PubMed] [Google Scholar]
- Brosnan J. T., Kopec B., Fritz I. B. The localization of carnitine palmitoyltransferase on the inner membrane of bovine liver mitochondria. J Biol Chem. 1973 Jun 10;248(11):4075–4082. [PubMed] [Google Scholar]
- Chase J. F., Tubbs P. K. Conditions for the self-catalysed inactivation of carnitine acetyltransferase. A novel form of enzyme inhibition. Biochem J. 1969 Jan;111(2):225–235. doi: 10.1042/bj1110225. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chase J. F., Tubbs P. K. Specific inhibition of mitochondrial fatty acid oxidation by 2-bromopalmitate and its coenzyme A and carnitine esters. Biochem J. 1972 Aug;129(1):55–65. doi: 10.1042/bj1290055. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chen R. F. Removal of fatty acids from serum albumin by charcoal treatment. J Biol Chem. 1967 Jan 25;242(2):173–181. [PubMed] [Google Scholar]
- Daum G. Lipids of mitochondria. Biochim Biophys Acta. 1985 Jun 12;822(1):1–42. doi: 10.1016/0304-4157(85)90002-4. [DOI] [PubMed] [Google Scholar]
- Edwards M. R., Bird M. I., Saggerson E. D. Effects of DL-2-bromopalmitoyl-CoA and bromoacetyl-CoA in rat liver and heart mitochondria. Inhibition of carnitine palmitoyltransferase and displacement of [14C]malonyl-CoA from mitochondrial binding sites. Biochem J. 1985 Aug 15;230(1):169–179. doi: 10.1042/bj2300169. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Federer W. T., Zelen M. Analysis of multifactor classifications with unequal numbers of observations. Biometrics. 1966 Sep;22(3):525–552. [PubMed] [Google Scholar]
- Fleischer S., Meissner G., Smigel M., Wood R. Preparation of submitochondrial vesicles using nitrogen decompression. Methods Enzymol. 1974;31:292–299. doi: 10.1016/0076-6879(74)31030-0. [DOI] [PubMed] [Google Scholar]
- Godinot C., Gautheron D. C. Separation of right-side-out and inside-out submitochondrial particles by affinity chromatography on Sepharose-cytochrome c. Methods Enzymol. 1979;55:112–114. doi: 10.1016/0076-6879(79)55015-0. [DOI] [PubMed] [Google Scholar]
- Grantham B. D., Zammit V. A. Binding of [14C]malonyl-CoA to rat liver mitochondria after blocking of the active site of carnitine palmitoyltransferase I. Displacement of low-affinity binding by palmitoyl-CoA. Biochem J. 1986 Jan 15;233(2):589–593. doi: 10.1042/bj2330589. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanson R. W., Ballard F. J. Citrate, pyruvate, and lactate contaminants of commercial serum albumin. J Lipid Res. 1968 Sep;9(5):667–668. [PubMed] [Google Scholar]
- Hoppel C. L. Carnitine and carnitine palmitoyltransferase in fatty acid oxidation and ketosis. Fed Proc. 1982 Oct;41(12):2853–2857. [PubMed] [Google Scholar]
- Hoppel C. L., Tomec R. J. Carnitine palmityltransferase. Location of two enzymatic activities in rat liver mitochondria. J Biol Chem. 1972 Feb 10;247(3):832–841. [PubMed] [Google Scholar]
- Hoppel C., DiMarco J. P., Tandler B. Riboflavin and rat hepatic cell structure and function. Mitochondrial oxidative metabolism in deficiency states. J Biol Chem. 1979 May 25;254(10):4164–4170. [PubMed] [Google Scholar]
- Kiorpes T. C., Hoerr D., Ho W., Weaner L. E., Inman M. G., Tutwiler G. F. Identification of 2-tetradecylglycidyl coenzyme A as the active form of methyl 2-tetradecylglycidate (methyl palmoxirate) and its characterization as an irreversible, active site-directed inhibitor of carnitine palmitoyltransferase A in isolated rat liver mitochondria. J Biol Chem. 1984 Aug 10;259(15):9750–9755. [PubMed] [Google Scholar]
- McGarry J. D., Foster D. W. Regulation of hepatic fatty acid oxidation and ketone body production. Annu Rev Biochem. 1980;49:395–420. doi: 10.1146/annurev.bi.49.070180.002143. [DOI] [PubMed] [Google Scholar]
- Mills S. E., Foster D. W., McGarry J. D. Effects of pH on the interaction of substrates and malonyl-CoA with mitochondrial carnitine palmitoyltransferase I. Biochem J. 1984 Apr 15;219(2):601–608. doi: 10.1042/bj2190601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miyazawa S., Ozasa H., Osumi T., Hashimoto T. Purification and properties of carnitine octanoyltransferase and carnitine palmitoyltransferase from rat liver. J Biochem. 1983 Aug;94(2):529–542. doi: 10.1093/oxfordjournals.jbchem.a134384. [DOI] [PubMed] [Google Scholar]
- Noël H., Goswami T., Pande S. V. Solubilization and reconstitution of rat liver mitochondrial carnitine acylcarnitine translocase. Biochemistry. 1985 Aug 13;24(17):4504–4509. doi: 10.1021/bi00338a003. [DOI] [PubMed] [Google Scholar]
- Pande S. V., Murthy M. S., Noël H. Differential effects of phosphatidylcholine and cardiolipin on carnitine palmitoyltransferase activity. Biochim Biophys Acta. 1986 Jun 27;877(2):223–230. doi: 10.1016/0005-2760(86)90298-5. [DOI] [PubMed] [Google Scholar]
- Saggerson E. D., Carpenter C. A. Carnitine palmitoyltransferase in liver and five extrahepatic tissues in the rat. Inhibition by DL-2-bromopalmitoyl-CoA and effect of hypothyroidism. Biochem J. 1986 May 15;236(1):137–141. doi: 10.1042/bj2360137. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tung A. S. Production of large amounts of antibodies, nonspecific immunoglobulins, and other serum proteins in ascitic fluids of individual mice and guinea pigs. Methods Enzymol. 1983;93:12–23. doi: 10.1016/s0076-6879(83)93032-x. [DOI] [PubMed] [Google Scholar]
- West D. W., Chase J. F., Tubbs P. K. The separation and properties of two forms of carnitine palmitoyltransferase from ox liver mitochondria. Biochem Biophys Res Commun. 1971 Mar 5;42(5):912–918. doi: 10.1016/0006-291x(71)90517-1. [DOI] [PubMed] [Google Scholar]
- Yates D. W., Garland P. B. Carnitine palmitoyltransferase activities (EC 2.3.1.-) of rat liver mitochondria. Biochem J. 1970 Sep;119(3):547–552. doi: 10.1042/bj1190547. [DOI] [PMC free article] [PubMed] [Google Scholar]