Determination of catechol-O-methyltransferase activity in various tissues by liquid chromatography

Shoup, Ronald E.; Davis, Gregory C.; Kissinger, Peter T.

doi:10.1021/ac50053a024

Cited by 40 publications

(14 citation statements)

References 19 publications

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“…Higher values were found for membrane COMT in all tissues studied (Nissinen, 1984). The 0-methylation ratios for human RBC S-COMT and MB-COMT, 5.29 and 15.5, respectively, are comparable with those in other tissues (Shoup et al, 1980;Nissinen, 1984).…”

supporting

confidence: 66%

“…Several assay procedures for RBC COMT have been described using 3H or I4C labelled SAM as cosubstrate and 3,4-dihydroxybenzoic acid (DBA) (Raymond and Weinshilboum, 1975;Floderus et al, 1981a) or natural catecholamines as substrates (Bates el al., 1979;Shoup et al, 1980;Levitt et al, 1982). A synthetic fluorogenic substrate has also been used (Nohta etal., 1984).…”

Section: Introductionmentioning

confidence: 99%

“…COMT activity in tissue homogenates has recently been measured using high-performance liquid chromatography (HPLC) with electrochemical detection (Shoup et al, 1980;Nissinen and Mannisto, 1984). We will now describe a method for determination of t Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

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Determination of catechol‐O‐methyltransferase activity in erythrocytes by high performance liquid chromatography with electrochemical detection

Schultz

Nissinen

Kaakkola

1989

Biomedical Chromatography

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A rapid assay employing HPLC with electrochemical detection for catechol-O-methyltransferase (COMT) activity in red blood cells is described. Enzyme activity is determined from erythrocyte lysates using S-adenosyl-L-methionine as methyl donor and 3,4-dihydroxybenzoic acid as substrate. The 3-O- and 4-O-methylated reaction products are measured by high-performance liquid chromatography with electrochemical detection. Human erythrocyte soluble form of COMT had Km values of 6.1 microM and 26.0 microM for S-adenosyl-L-methionine and dihydroxybenzoic acid, respectively. The mean O-methylation ratio for the soluble form of COMT was 5.3. An O-methylation ratio of 15.5 was estimated in the membrane fraction of an erythrocyte pool from three samples. The activities of soluble COMT in erythrocytes of some animal species are also reported. The procedure is easily automated, and a large number of samples can be processed during one working day.

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supporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

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Determination of catechol‐O‐methyltransferase activity in erythrocytes by high performance liquid chromatography with electrochemical detection

Schultz

Nissinen

Kaakkola

1989

Biomedical Chromatography

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“…At this point the valve is switched and dopamine is eluted off the first column directly to waste without passing over the working electrode. Assays have also been developed for tyrosine hydroxylase (Blank and Pike, 1976;N agatsu et at., 1979), dopa-decarboxylase (Christensen and Blank, 1979), phenylethanolamine-N-transferase (PNMT) (Borchardt et at., 1977), and catechol-O-methyltransferase (Borchardt et at., Shoup et at., 1980). It can be anticipated that methods will appear to measure tryptophan hydroxylase and 5-HTP-decarboxylase, and preliminary reports of such determinations are available (e.g., Blank et at., 1980).…”

Section: Enzyme Assaysmentioning

confidence: 99%

Electrochemical Detection Methods for Monoamine Measurements in Vitro and in Vivo

Adams

Marsden

1982

Handbook of Psychopharmacology

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“…Dopamine was purified according to the type method of Shoup et al (1980). Amberlite used for adsorption of DOPAL was conditioned by the method of Pisano (1960).…”

Section: Methodsmentioning

confidence: 99%

Kinetic Interactions of Dopamine and Dobutamine with Human Catechol-O-methyltransferase and Monoamine Oxidase in Vitro

Yan¹,

Webster²,

Blumer³

2002

J Pharmacol Exp Ther

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Dopamine and dobutamine are often infused together into acutely ill patients requiring temporary support of cardiac and renal function, but whether these catecholamines affect the metabolic clearance of each other is not established. We determined the kinetics of dopamine and dobutamine as substrates and inhibitors of each other, i.e., apparent V max , K m , and K i , with crude preparations of human blood mononuclear cell catechol-O-methyltransferase (COMT) and platelet monoamine oxidase (MAO) at pH 7.4 and 37°C. Values of V max for dopamine and dobutamine as substrates for COMT were 0.45 and 0.59 nmol of 3-O-methyl product formed per milligram of protein per minute, whereas those for K m were 0.44 and 0.05 mM, respectively. Dopamine and dobutamine were competitive inhibitors of each other in this reaction. The K i for dopamine as an inhibitor of dobutamine methylation was 1.5 mM, whereas that for dobutamine as an inhibitor of dopamine methylation was 0.015 mM. Dopamine but not dobutamine was a substrate for MAO. The V max for dihydroxyphenylacetaldehyde formation from dopamine was 0.29 nmol/mg protein/min and the K m for dopamine was 0.38 mM. Dobutamine was a noncompetitive inhibitor of dopamine oxidation in this reaction (K i Х 1.19 mM). The high apparent K m and K i values derived for dopamine and dobutamine when tested with these two human enzymes in vitro suggest that these catecholamines do not interfere with the metabolism of each other when both are infused together at therapeutic concentrations.Dopamine and dobutamine are catecholamines commonly infused together to treat critically ill patients with shock and/or heart failure. Dopamine is a biogenic amine given at low doses to maintain or enhance renal and splanchnic perfusion, whereas dobutamine is a chemically related synthetic inotrope employed to enhance cardiac output without increasing systemic vascular resistance (Latifi et al., 2000). Whether dopamine and dobutamine affect the systemic clearance of each other when both compounds are administered together is unclear from reports of three pharmacokinetic studies (Banner et al., 1989(Banner et al., , 1991Schwartz et al., 1991).Catechol-O-methyltransferase (COMT) and monoamine oxidase (MAO) are the two enzymes primarily responsible for the initial metabolic disposition of infused catecholamines in the blood of mammals (Kopin, 1985). Moreover, formation of 3-O-methyldobutamine catalyzed by COMT appears to be the main route for dobutamine biodisposition in the dog (Murphy et al., 1976), and we have recently shown that 3-O-methyldobutamine is a major product of infused dobutamine metabolism in humans (Yan et al., 2002). To our knowledge there is no published information as to whether dobutamine serves as a substrate for MAO in humans.To evaluate the roles of COMT and MAO in the metabolic clearance of coinfused dopamine and dobutamine and in possible metabolic interactions between these two inotropes in humans, we now report kinetic studies of dopamine and dobutamine used both as substrates and...

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Determination of catechol-O-methyltransferase activity in various tissues by liquid chromatography

Cited by 40 publications

References 19 publications

Determination of catechol‐O‐methyltransferase activity in erythrocytes by high performance liquid chromatography with electrochemical detection

Determination of catechol‐O‐methyltransferase activity in erythrocytes by high performance liquid chromatography with electrochemical detection

Electrochemical Detection Methods for Monoamine Measurements in Vitro and in Vivo

Kinetic Interactions of Dopamine and Dobutamine with Human Catechol-O-methyltransferase and Monoamine Oxidase in Vitro

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