5-methyltetrahydrofolic acid is not a methyl donor for biogenic amines: enzymatic formation of formaldehyde

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Science  17 Jan 1975:
Vol. 187, Issue 4172, pp. 171-173
DOI: 10.1126/science.1111095


Contrary to previous reports, 5-methyltetrahydrofolic acid does not mediate the methylation of dopamine to epinine. Instead, this methyl donor is degraded enzymatically to formaldehyde, which condenses with dopamine to form a tetahydoisoquinoline derivative. The latter has chromotographic characteristics very similar to those of epinine, which likely accounts for the original misidentification of the product.