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Updated: Sep 30, 2026

MALDI Imaging Mass Spectrometry of Neuropeptides in Parkinson's Disease
Published on: February 14, 2012
3-OMD and homocysteine plasma levels in parkinsonian patients
Th Müller1, D Woitalla, B Fowler
1Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Federal Republic of Germany. thomas.mueller@ruhr-uni-bochum.de
Abstract:
One main metabolizing pathway of levodopa is O-methylation to 3-O-methyldopa (3-OMD) by catechol-O-methyltransferase (COMT). Since COMT requires Mg2+ and S-adenosylmethionine as methyl donor for this transmethylating process, COMT converts S-adenosylmethionine to S-adenosylhomocysteine and subsequent homocysteine. Objective of this study was to demonstrate relations between plasma levodopa, 3-OMD and total homocysteine in treated parkinsonian subjects. We measured homocysteine, levodopa and 3-OMD by HPLC. We compared plasma homocysteine in two groups of treated parkinsonian subjects subdivided according to their 3-OMD level. Homocysteine was significantly (p = 0.002) elevated in the group with higher 3-OMD concentrations and positively (r = 0.52, p = 0.0006) correlated to 3-OMD. Homocysteine induces vascular disease. Previous studies showed an increase of ischaemic heart- and cerebrovascular disease in treated parkinsonian patients.
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