Subcellular distribution of aldehyde dehydrogenase activities in human liver |
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| Authors: | G T Henehan K Ward N P Kennedy D G Weir K F Tipton |
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| Institution: | 1. Department of Biochemistry, Trinity College, Dublin 2, Ireland;2. Department of Medicine, St. James''s Hospital, Dublin 8, Ireland |
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| Abstract: | The subcellular distributions of aldehyde dehydrogenase activities towards acetaldehyde have been determined in wedge-biopsy samples of human liver. A form with Km values of less than 1 microM and 285 microM towards acetaldehyde and NAD+ respectively was present in the mitochondrial fraction. This enzyme had no detectable activity towards N-tele-methylimidazole acetaldehyde, the aldehyde derived from the oxidation of N-tele-methylhistamine. The activity in the cytosol was more sensitive to inhibition by disulfiram and had Km values of 270 microM and 25 microM for acetaldehyde and NAD+, respectively. It was active towards N-tele-methylimidazole acetaldehyde with a Km value of 2.5 microM and a maximum velocity that was 40% of that determined with acetaldehyde. Both these cytosolic activities had alkaline pH optima. |
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| Keywords: | Aldehyde dehydrogenase subcellular localization Acetaldehyde oxidation by aldehyde dehydrogenase Disulfiram inhibition of aldehyde dehydrogenase Histamine metabolism Requests for reprints should be addressed to K F Tipton |
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