Premium
Monoamine Oxidase‐Catalyzed Metabolism of 3,4‐Dihydroxyphenylethylamine in the Dopaminergic Synaptosomes from Rat Corpus Striatum
Author(s) -
Katz Ira R.
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb08713.x
Subject(s) - monoamine oxidase , dopaminergic , dopamine , striatum , chemistry , substrate (aquarium) , catecholamine , biochemistry , monoamine neurotransmitter , enzyme , metabolism , biophysics , biology , neuroscience , serotonin , ecology , receptor
This communication describes conditions under which the monoamine oxidase‐catalyzed metabolism of 3,4‐dihydroxyphenylethylamine can be assayed in dopaminergic synaptosomes from the rat striatum. In contrast to the activity of the isolated enzyme or that of free mitochondria, the synaptosomal reaction exhibits sigmoidal kinetics with respect to substrate concentration. This is consistent with a kinetic mechanism in which intrasynaptosomal substrate partitions between reaction and saturable storage in synaptic vesicles. The reaction is inhibited at moderately decreased oxygen tension, where catecholamine uptake is unaffected. The specificity of this effect suggests that it reflects limited availability of oxygen as an enzyme substrate.