The major objective of the proposed research program is to elucidate regulatory mechanisms for two multienzyme complexes involved in mirochondrial energy production in cardiac tissue. The regulation of the pyruvate and the branched chain Alpha-keto acid dehydrogenase enzyme complexes by two forms of covalent modification (e.g., phosphorylation and acylation) will be investigated using the purified enzyme complexes from bovine heart, isolated rat heart mitochondria and in the isolated perfused rat heart. Experimental support will be sought for our contention that these two enzyme complexes are activated by their respective natural substrates but inactivated by the substrates for the other complex, e.g., pyruvate activates pyruvate dehydrogenase but inactivate the branched chain complex while the branched chain Alpha-keto acids activate the branched chain complex but inactivate the pyruvate complex. Of particular interest will be our suggestion that the pyruvate dehydrogenase kinase may be regulated by acylation/acetylation by various Alpha-keto acid substrates or Coenzyme A derivatives. Finally, the effects of various metabolic and hormonal states on the regulation of the pyruvate and branched chain dehydrogenase complexes will be investigated in perfused heart preparations. Experiments are proposed to test a suggestion that insulin exerts its stimulatory effect on the pyruvate dehydrogenase complex through an effect of a (e.g., disulfide containing) mediator substance on a reactive thiol moiety on the pyruvate dehydrogenase kinase. It is anticipated that the proposed studies will provide a necessary and unique perception of how the regulation of these two very important enzyme complexes is crucial for the maintenance of an appropriate energy generating capability in my myocardium.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL024654-08
Application #
3337796
Study Section
Biochemistry Study Section (BIO)
Project Start
1979-08-01
Project End
1990-06-30
Budget Start
1987-07-01
Budget End
1988-06-30
Support Year
8
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Texas Health Science Center San Antonio
Department
Type
School of Medicine & Dentistry
DUNS #
800772162
City
San Antonio
State
TX
Country
United States
Zip Code
78229
De Marcucci, O L; DeBuysere, M S; Olson, M S (1995) Dissociation and reassembly of the dihydrolipoyl transacetylase component of the bovine heart pyruvate dehydrogenase complex. Arch Biochem Biophys 323:169-76
Pawelczyk, T; Easom, R A; Olson, M S (1994) The dependence of electrophoretic and spectroscopic properties of the pyruvate dehydrogenase complex on mono- and divalent ions. Acta Biochim Pol 41:63-72
Behal, R H; DeBuysere, M S; Demeler, B et al. (1994) Pyruvate dehydrogenase multienzyme complex. Characterization of assembly intermediates by sedimentation velocity analysis. J Biol Chem 269:31372-7
Pawelczyk, T; Olson, M S (1993) Comparison of the kinetic properties of the pyruvate dehydrogenase complex from pig kidney cortex and medulla. Acta Biochim Pol 40:411-9
Pawelczyk, T; Olson, M S (1993) The regulatory properties of kidney pyruvate dehydrogenase complex components. Arch Biochem Biophys 300:489-94
Behal, R H; Buxton, D B; Robertson, J G et al. (1993) Regulation of the pyruvate dehydrogenase multienzyme complex. Annu Rev Nutr 13:497-520
Pawelczyk, T; Easom, R A; Olson, M S (1992) Effect of ionic strength and pH on the activity of pyruvate dehydrogenase complex from pig kidney cortex. Arch Biochem Biophys 294:44-9
Pawelczyk, T; Olson, M S (1992) Regulation of pyruvate dehydrogenase kinase activity from pig kidney cortex. Biochem J 288 ( Pt 2):369-73
Robertson, J G; Barron, L L; Olson, M S (1990) Bovine heart pyruvate dehydrogenase kinase stimulation by alpha-ketoisovalerate. J Biol Chem 265:16814-20
Olson, M S (1989) Regulation of the mitochondrial multienzyme complexes in complex metabolic systems. Ann N Y Acad Sci 573:218-29

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