Occurrence of aromatic L-amino acid decarboxylase in human plasma and its assay by high-performance liquid chromatography with fluorescence detection.
A high-performance liquid chromatographic method using fluorescence detection for assessing the activity of aromatic L-amino acid decarboxylase in human plasma is described. Dopamine, formed enzymatically from L-DOPA, and isoproterenol (internal standard) are chromatographed on a small ion-exchange cartridge (Toyopak SP) and derivatized with 1,2-diphenylethylenediamine. The derivatives are separated by reversed-phase chromatography on an Ultrasphere ODS column. The detection limit for dopamine formed enzymatically is 0.6 pmol per 500 microliter of enzyme reaction mixture. Aromatic L-amino acid decarboxylase in human plasma is very similar to that in rat kidney, with respect to optimum conditions for the enzyme reaction and gel chromatographic behaviour.
D000328:Adult; D000818:Animals; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000097:blood*; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007202:Indicators and Reagents; D007668:Kidney / Q000201:enzymology; D008875:Middle Aged; D051381:Rats; D013050:Spectrometry, Fluorescence
D007202:Indicators and Reagents; D001142:Aromatic-L-Amino-Acid Decarboxylases