A new and highly sensitive voltammetric assay for aromatic l-amino acid decarboxylase activity by high-performance liquid chromatography

✍ Scribed by Toshiharu Nagatsu; Toshifumi Yamamoto; Takeshi Kato

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 516 KB
• Volume: 100
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(79)90126-x

✦ Synopsis

This paper describes a new, inexpensive, and highly sensitive voltammetric assay for aromatic L-amino acid decarboxylase (AADC) activity in rat and human brains by highperformance liquid chromatography (hplc). L-Dopa was used as substrate and D-dopa for the blank. After isolating dopamine formed enzymatically from L-dopa on a small Amberlite CG-50 column, the dopamine in the column eluate was assayed by hplc with a voltammetric detector. Dihydroxybenzylamine was added to each incubation mixture as an internal standard and therefore this assay was highly reproducible. The peak height in hplc was linear from 100 fmol to 100 pmol of dopamine. The values obtained by this method agreed with those by radioassay using [I-"C]dopa. The enzyme activity in rat cerebra) cortex and in Parkinsonian caudate nucleus, in which the activity was too low to be measured even with the radioassay, could be measured accurately.