DOI: 10.1177/10.3.348 ISSN:

FLUORESCENCE OF CATECHOL AMINES AND RELATED COMPOUNDS CONDENSED WITH FORMALDEHYDE

B. FALCK, N.-Å. HILLARP, G. THIEME, A. TORP
  • Histology
  • Anatomy
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The reaction under mild conditions between formaldehyde and phenylalanine and phenylethylamine derivatives has been studied. When the amines included in a dried protein film were exposed to formaldehyde vapour a very intense green to yellow fluorescence was give only by those that as well as being primary amines also have hydroxyl groups at the 3 and 4 positions (3,4-dihydroxyphenylalanine, dopamine, noradrenaline). The 3-OH group seems to be esssential for the reaction. The catechol amines, which are secondary amines (adrenaline, epinine), gave a much weaker fluorescence that developed more slowly.

The results obtained on further examination of the reaction favour the view that the amines primarily condense with formaldehyde to 1,2,3,4-tetrahydroisoquinolines which are involved in a secondary reaction to become highly fluorescent and at the same time insoluble. This secondary reaction may be a binding to protein, and oxidation with the formation of double bonds in the heterocyclic ring, or both.

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