Brain monoamine oxidase and replacement of its coenzyme flavin in rats
Dix, B.A.; Lambooy, J.P.
Journal of Nutrition 111(8): 1397-1402
1981
ISSN/ISBN: 0022-3166 PMID: 7264772 Document Number: 178617
The influence of 7-ethyl-8-methylflavin and 7-methyl-8-ethylflavin, vitamin-like homologues of riboflavin, on rat brain mitochondrial monoamine oxidase (MAO) was studied with tyramine as substrate. Although riboflavin deficiency caused the enzyme activity to fall to 80% of normal, when 7-ethyl-8-methylflavin replaced riboflavin as the precursor of its coenzyme it caused the activity to fall to 60% of normal. When 7-methyl-8-ethylflavin replaced riboflavin as the precursor of its coenzyme, it caused complete loss of the enzyme activity. The findings showed that whereas 7-ethyl-8-methylflavin can serve as a coenzyme for MAO, 7-methyl-8-ethylflavin cannot serve as coenzyme for this enzyme.