William F. Bosron Professor, (past)

Structure and mechanism of alcohol dehydrogenases and carboxylesterases; regulation of ethanol, retinoid and drug ester (cocaine, heroin, meperidine) metabolism; role of retinoid metabolism in liver fibrosis.

My general research interests are in the mechanism of enzyme action and the regulation of drug metabolism. We have characterized nine different genetic variants (isoenzymes) of human alcohol dehydrogenase. I am interested in correlating amino acid and three-dimensional sturctural relationships for these isoenzymes with their functional in ethanol, retinol and isoprenoid alcohol metabolism. The substrate binding, steady-state kinetics, and stopped-flow presteady-state kinetics of naturally occurring human liver alcohol dehydrogenase isoenzymes and mutant forms created by site-directed mutagenesis of a human alcohol dehydrogenase cDNA are being examined. For those enzyme forms exhibiting unique catalytic properties, their molecular structures are being analyzed by X-ray crystallography and fluorescence.

I am interested in the identification and characterization of esterases involved in the metabolism of cocaine, heroin, opoid ester and anti-cancer prodrug (CPT-11 and Capecitabine). In particular, I am interested in the substrate specificity, expression and structure of human carboxylesterase isoenzymes CES1, CES2 and CES3. We are using steady-state kinetics, stopped-flow kinetics and X-ray crystallography to examine structure-function relationship among the carboxylesterases. We are prearing expressed carboxylesterases and transfected cell lines to examine the extent of carboxylesterase-mediated hydrolysis of candidate drugs using LC/MS analysis of metabolites.

I am interested in the kinetic and molecular characterization of retinyl ester hydrolases and retinol dehydrogenases. In particular, I am studying the expression of these enzymes in liver stellate cells during the time that they lose their retinoid-containing intracellular droplets and undergo activation to form myofibroblast-like cells. The retinoid depletion and stellate cell activation are an important step in alcohol-induced liver fibrosis and cirrhosis. We are using fluorescence-activated cell sorting, immunocytochemistry, fluorescence microscopy and real-time PCR to examine the expression of retinoid metabolizing enzymes and myofibrobast markers to examine the time course of retinoid depletion and stellate cell activation. Research:
My general research interests are in the mechanism of enzyme action and the regulation of drug metabolism. We have characterized nine different genetic variants (isoenzymes) of human alcohol dehydrogenase. I am interested in correlating amino acid and three-dimensional structural relationships for these isoenzymes with their function in ethanol, retinol, and isoprenoid alcohol metabolism. The substrate binding, steady-state kinetics, and stopped-flow presteady-state kinetics of naturally occurring human liver alcohol dehydrogenase isoenzymes and mutant forms created by site-directed mutagenesis of a human alcohol dehydrogenase cDNA are being examined. For those enzyme forms exhibiting unique catalytic properties, their molecular structures are being analyzed by X-ray crystallography and fluorescence.

I am interested in the identification and characterization of esterases involved in cocaine, heroin, opoid ester, and CPT-11 metabolism. In particular, I am interested in the enzymatic mechanism of formation and pharmacologic properties of a unique derivative of cocaine, cocaethylene, which is formed in individuals simultaneously taking cocaine and ethanol. The kinetic and molecular properties of the purified carboxylesterases involved in drug ester metabolism are being examined.

I am interested in the kinetic and molecular characterization of retinol dehydrogenases and retinyl ester hydrolases. In particular, I am studying the expression of these enzymes in liver stellate cells during the time that they lose their retinoid-containing intracellular droplets and undergo activation to form myofibroblast-like cells. The characterization of the role of retinoid metabolism in these cells will be important to the understanding of early events in alcohol-induced liver fibrosis and cirrhosis. General research interests are in the mechanism of enzyme action and the regulation of drug metabolism. Research:
My general research interests are in the mechanism of enzyme action and the regulation of drug metabolism. We have characterized nine different genetic variants (isoenzymes) of human alcohol dehydrogenase. I am interested in correlating amino acid and three-dimensional structural relationships for these isoenzymes with their function in ethanol, retinol, and isoprenoid alcohol metabolism. The substrate binding, steady-state kinetics, and stopped-flow presteady-state kinetics of naturally occurring human liver alcohol dehydrogenase isoenzymes and mutant forms created by site-directed mutagenesis of a human alcohol dehydrogenase cDNA are being examined. For those enzyme forms exhibiting unique catalytic properties, their molecular structures are being analyzed by X-ray crystallography and fluorescence.

I am interested in the identification and characterization of esterases involved in cocaine, heroin, opoid ester, and CPT-11 metabolism. In particular, I am interested in the enzymatic mechanism of formation and pharmacologic properties of a unique derivative of cocaine, cocaethylene, which is formed in individuals simultaneously taking cocaine and ethanol. The kinetic and molecular properties of the purified carboxylesterases involved in drug ester metabolism are being examined.

I am interested in the kinetic and molecular characterization of retinol dehydrogenases and retinyl ester hydrolases. In particular, I am studying the expression of these enzymes in liver stellate cells during the time that they lose their retinoid-containing intracellular droplets and undergo activation to form myofibroblast-like cells. The characterization of the role of retinoid metabolism in these cells will be important to the understanding of early events in alcohol-induced liver fibrosis and cirrhosis.