5-Methyltetrahydrofolic Acid Is Not a Methyl Donor for Biogenic Amines: Enzymatic Formation of Formaldehyde

Abstract
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.
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