Determination of human serum alcohol dehydrogenase using isozyme-specific fluorescent substrates.
Both class I and class II alcohol dehydrogenase (ADH) activities are present in human serum. The contribution of each class can be measured using two class-specific, fluorogenic substrates, 4-methoxy-1-naphthaldehyde and 6-methoxy-2-naphthaldehyde. The former is highly selective for class I isozymes, especially those containing alpha or gamma subunits, whereas class II (pi) ADH preferentially reduces the latter. Selective inhibition of class I ADH by 4-methylpyrazole further increases the specificity. Specificity, accuracy, and precision of the assay for serum measurements have been determined. The activity of class I ADH in normal human serum is below the limit of detection of this method, i.e., less than 1.0 nM/min. The activity of class II ADH in normal individuals is 15 +/- 5 nM/min. In some patients values as high as 2100 nM/min are observed for class I, but in all instances, the amount of class II found was higher than that of class I ADH.
Wierzchowski
J
J
Center for Biochemical and Biophysical Sciences, Harvard Medical School, Boston, Massachusetts 02115.
Holmquist
B
B
Vallee
B L
BL
D000426:Alcohol Dehydrogenase / Q000097:blood*; D000447:Aldehydes / Q000378:metabolism; D005456:Fluorescent Dyes / Q000737:chemistry*; D000077604:Fomepizole; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D009281:Naphthalenes / Q000378:metabolism; D010084:Oxidation-Reduction; D011720:Pyrazoles / Q000494:pharmacology; D013379:Substrate Specificity
D000447:Aldehydes; D005456:Fluorescent Dyes; D007527:Isoenzymes; D009281:Naphthalenes; D011720:Pyrazoles; C059869:4-methoxy-1-naphthalaldehyde; C059868:6-methoxy-2-naphthalaldehyde; D000077604:Fomepizole; D000426:Alcohol Dehydrogenase