The overall objective is to clarify poorly understood aspects of 3- hydroxyisobutyrate formation and utilization. The work will focus on 3- hydroxyisobutyryl-CoA hydrolase, 3-hydroxyisobutyrate dehydrogenase, and methylmalonate semialdehyde dehydrogenase. It is proposed that the hydrolase responsible for 3-hydroxyisobutyrate formation has specificity for thiolytic cleavage of 3-hydroxyiso-butyryl-CoA at physiological concentrations at which CoA esters of metabolic pathways occur, that the hydrolase plays an important role in preventing the accumulation of potentially cytotoxic, mutagenic and clastogenic concentrations of 3- methacrylyl-CoA and acrylyl-CoA, that 3-hydroxyisobutyryl-CoA hydrolase also functions to prevent coenzyme A sequestration by drugs and in genetic/metabolic disorders, that the brain contains a broad-specificity, short chain acyl-CoA hydrolase for unique protection of this tissue against CoA sequestration, that colonic epithelial cells must have a very active catabolic pathway to protect against toxicity of isobutyrate produced by large bowel bacteria, and that both short-term (inhibition by acylation) and long-term (regulation of expression) mechanisms regulate the activity of methylmalonate semialdehyde dehydrogenase. The detailed specific aims are: (a) to purify and clone 3-hydroxyisobutyryl-CoA hydrolase; (b) to determine substrate specificity and tissue distribution of 3-hydroxyisobutyryl-CoA hydrolase and whether it (or enzymes of the same family) is responsible for protection against cytotoxic effects of methacrylyl-CoA as well as CoA sequestration by various drugs and blockage of metabolic pathways; (c) to purify and clone the broad-specificity short chain acyl-CoA hydrolase present in brain tissue; (d) to establish the metabolic fate of the isobutyrate produced by colonic bacteria; and (e) to establish the mechanisms responsible for short-term regulation of methylmalonate semialdehyde dehydrogenase activity and long-term regulation of methylmalonate semialdehyde dehydrogenase expression. The work on acyl-CoA hydrolase(s) is relevant to the teratogenic/clastogenic response to acrylate/methacrylate compounds and to elucidation of the cellular defense mechanisms against CoA sequestration caused by foreign compounds (ibuprofen, valproate, clofibrate) and genetic/metabolic disorders (methylmalonyl mutase deficiency, vitamin B12 deficiency, biotin deficiency). Overall the work will clarify poorly understood features of the valine, thymine, and beta-alanine catabolic pathways

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK040441-09
Application #
2444016
Study Section
Biochemistry Study Section (BIO)
Program Officer
Laughlin, Maren R
Project Start
1988-09-01
Project End
1999-06-30
Budget Start
1997-07-15
Budget End
1999-06-30
Support Year
9
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Biochemistry
Type
Schools of Medicine
DUNS #
005436803
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Popov, K M; Shimomura, Y; Hawes, J W et al. (2000) Branched-chain alpha-keto acid dehydrogenase kinase. Methods Enzymol 324:162-78
Hawes, J W; Crabb, D W; Chan, R J et al. (2000) Mammalian 3-hydroxyisobutyrate dehydrogenase. Methods Enzymol 324:218-28
Kedishvili, N Y; Goodwin, G W; Popov, K M et al. (2000) Mammalian methylmalonate-semialdehyde dehydrogenase. Methods Enzymol 324:207-18
Shimomura, Y; Murakami, T; Nakai, N et al. (2000) 3-hydroxyisobutyryl-CoA hydrolase. Methods Enzymol 324:229-40
Nakai, N; Kobayashi, R; Popov, K M et al. (2000) Determination of branched-chain alpha-keto acid dehydrogenase activity state and branched-chain alpha-keto acid dehydrogenase kinase activity and protein in mammalian tissues. Methods Enzymol 324:48-62
Hawes, J W; Harper, E T; Crabb, D W et al. (1997) Structural and mechanistic aspects of a new family of dehydrogenases, the beta-hydroxyacid dehydrogenases. Adv Exp Med Biol 414:395-402
Jaskiewicz, J; Zhao, Y; Hawes, J W et al. (1996) Catabolism of isobutyrate by colonocytes. Arch Biochem Biophys 327:265-70
Hawes, J W; Jaskiewicz, J; Shimomura, Y et al. (1996) Primary structure and tissue-specific expression of human beta-hydroxyisobutyryl-coenzyme A hydrolase. J Biol Chem 271:26430-4
Hawes, J W; Harper, E T; Crabb, D W et al. (1996) Structural and mechanistic similarities of 6-phosphogluconate and 3-hydroxyisobutyrate dehydrogenases reveal a new enzyme family, the 3-hydroxyacid dehydrogenases. FEBS Lett 389:263-7
Taniguchi, K; Nonami, T; Nakao, A et al. (1996) The valine catabolic pathway in human liver: effect of cirrhosis on enzyme activities. Hepatology 24:1395-8

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