Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Journal of neurochemistry
33 (1979), S. 0
ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract— A single isotope radioenzymatic procedure for the measurement of DOPA has been developed. The assay combines O-methylation of DOPA by purified COMT using [3H]SAM as the methyl donor and subsequent purification as the DNFB derivative of 3-O-[methyl-3H]DOPA. The present method is about 100 times more sensitive than currently available DOPA methods. This is due to decreased blank values and increased enzymatic conversion giving transmethylation values of 50% with tissue extracts and values of almost 100% with pure solutions. Although COMT methylates a wide variety of catechol compounds, specificity of the assay is achieved by selective extraction and purification of the final product by tlc.The method has good inter-assay reliability, the coefficient of variation being about 3.5%.This ultramicromethod was used to determine the steady-state concentrations of endogenous DOPA in minute samples of brain areas of the rat. In untreated rats brain DOPA levels varied with the mode of death; the highest levels were found in animals killed by microwave irradiation. Unconjugated DOPA was measured in microlitre aliquots of human body fluids.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1471-4159.1979.tb05207.x
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