Human aldehyde dehydrogenase. Activity with aldehyde metabolites of monoamines, diamines, and polyamines.

摘要: Two isozymes (E1 and E2) of human aldehyde dehydrogenase (EC 1.2.1.3) were purified to homogeneity 13 years ago a third isozyme (E3) with low Km for gamma-aminobutyraldehyde only recently. Comparison variety substrates demonstrates that substrate specificity all three is broad similar. With straight chain aliphatic aldehydes (C1-C6) the values E3 are identical those E1 isozyme. All dehydrogenate naturally occurring aldehydes, 5-imidazoleacetaldehyde (histamine metabolite) acrolein (product beta-elimination oxidized polyamines) similar catalytic efficiency. Differences between in aminoaldehydes. Although can gamma-aminobutyraldehyde, value much lower: same appears apply metabolites cadaverine, agmatine, spermidine, spermine which range 2-18 microM kcat 0.8-1.9 mumol/min/mg. Thus, has properties make it suitable metabolism The physiological role E2 could be dehydrogenation monoamines such as 3,4-dihydroxyphenylacetaldehyde or 5-hydroxyindoleacetaldehyde; efficiency these better than Isoelectric focusing liver homogenates followed by development various together data suggest enzyme capable catalyzing arising via monoamine, diamine, plasma amine oxidases. generally considered function detoxication, our an additional biogenic amines.