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. 1996 Feb 1;313(Pt 3):849–853. doi: 10.1042/bj3130849

Evidence for a single non-arachidonic acid-specific fatty acyl-CoA synthetase in heart which is regulated by Mg2+.

C Saunders 1, J M Voigt 1, M T Weis 1
PMCID: PMC1216988  PMID: 8611165

Abstract

Previous reports indicated that arachidonic acid is incorporated into the isolated perfused rabbit heart in preference to other fatty acids, and that incorporation of arachidonic acid, but not other fatty acids, is inhibited during Mg2+ depletion. In this study, we have not been able to demonstrate an arachidonic acid-specific fatty acyl-CoA synthetase in rat or rabbit heart by hydroxyapatite chromatography. Kinetic evidence was consistent with a single enzyme, as the slopes of pseudo-Hill plots were not significantly different from -1. The single fatty acyl-CoA synthetase present appears to prefer C18:0 unsaturated fatty acids to arachidonate, and had about the same affinity for C10:0 -C14:0 saturated fatty acids as for arachidonate. At 35 microM arachidonate, enzyme velocity increased as the total Mg2+ was increased from 3 to 80 mM. Calculated [MgATP] indicated that the MgATP complex was not rate-limiting. At low concentrations, Mn2+ and Ni2+ supported activity, but Cu2+ and Zn2+ did not. Low Ca2+ concentrations activated only oleic acid conversion. Kinetic analysis indicated that the Vmax of the enzyme was increased with increasing concentrations of ionized Mg2+ for both oleic acid and arachidonic acid. The data are constant with the hypothesis that Mg2+ has a direct effect on fatty acyl-CoA synthetase activity, and suggest that preference for oleic acid and arachidonic acid can be influenced by the ionic milieu.

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Selected References

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  1. Brumfeld V., Lester D. S. Protein kinase C penetration into lipid bilayers. Arch Biochem Biophys. 1990 Mar;277(2):318–323. doi: 10.1016/0003-9861(90)90586-n. [DOI] [PubMed] [Google Scholar]
  2. Garfinkel L., Garfinkel D. Calculation of free-Mg2+ concentration in adenosine 5'-triphosphate containing solutions in vitro and in vivo. Biochemistry. 1984 Jul 17;23(15):3547–3552. doi: 10.1021/bi00310a025. [DOI] [PubMed] [Google Scholar]
  3. King M. M. Conformation-sensitive modification of the type II calmodulin-dependent protein kinase by phenylglyoxal. J Biol Chem. 1988 Apr 5;263(10):4754–4757. [PubMed] [Google Scholar]
  4. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  5. Laposata M., Reich E. L., Majerus P. W. Arachidonoyl-CoA synthetase. Separation from nonspecific acyl-CoA synthetase and distribution in various cells and tissues. J Biol Chem. 1985 Sep 15;260(20):11016–11020. [PubMed] [Google Scholar]
  6. Lester D. S., Brumfeld V. Divalent cation-induced changes in conformation of protein kinase C. Biophys Chem. 1991 Feb;39(2):215–224. doi: 10.1016/0301-4622(91)85024-k. [DOI] [PubMed] [Google Scholar]
  7. Lester D. S., Brumfeld V. Ligand-induced conformational changes in cytosolic protein kinase C. Int J Biol Macromol. 1990 Aug;12(4):251–256. doi: 10.1016/0141-8130(90)90005-u. [DOI] [PubMed] [Google Scholar]
  8. Mishina M., Kamiryo T., Tashiro S., Numa S. Separation and characterization of two long-chain acyl-CoA synthetases from Candida lipolytica. Eur J Biochem. 1978 Jan 16;82(2):347–354. doi: 10.1111/j.1432-1033.1978.tb12029.x. [DOI] [PubMed] [Google Scholar]
  9. Vicario P. P., Bennun A. Separate effects of Mg2+, MgATP, and ATP4- on the kinetic mechanism for insulin receptor tyrosine kinase. Arch Biochem Biophys. 1990 Apr;278(1):99–105. doi: 10.1016/0003-9861(90)90236-r. [DOI] [PubMed] [Google Scholar]
  10. Weis M. T. Magnesium influences incorporation of [3H]arachidonic acid in perfused rabbits hearts. Am J Physiol. 1993 Jul;265(1 Pt 2):H83–H90. doi: 10.1152/ajpheart.1993.265.1.H83. [DOI] [PubMed] [Google Scholar]
  11. Weis M. T., Palazzo A. J., Williams J. L., Jr, Malik K. U. Uptake, incorporation and metabolism of (3H)triolein in the isolated perfused rabbit heart. Lipids. 1990 Aug;25(8):497–503. doi: 10.1007/BF02538094. [DOI] [PubMed] [Google Scholar]
  12. Weis M. T., Saunders C. Magnesium and arachidonic acid metabolism. Magnes Res. 1993 Jun;6(2):179–190. [PubMed] [Google Scholar]
  13. Wilson D. B., Prescott S. M., Majerus P. W. Discovery of an arachidonoyl coenzyme A synthetase in human platelets. J Biol Chem. 1982 Apr 10;257(7):3510–3515. [PubMed] [Google Scholar]

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