The role of 2,4,5-trihydroxyphenylalanine in melanin biosynthesis

J Biol Chem. 1977 Aug 25;252(16):5729-34.

Abstract

Both 3,4-dihydroxyphenylalanine and 2,4,5-trihydroxyphenylalanine were oxidized with periodate and mushroom tyrosinase to determine whether the latter compound is an intermediate in melanin biosynthesis. Matrix analysis of the spectra obtained with a rapid scan spectrophotometer and comparison of the spectra of quinone intermediates with model quinones disclosed that, although 2,4,5-trihydroxyphenylalanine can be oxidized to 2-carboxy-2,3-dihydroindole-5,6-quinone (dopachrome), this oxidation proceeds through a stable intermediate, 5-(2-carboxy-2-aminoethyl)-2-hydroxy-1,4-benzoquinone, which does not appear in the oxidation of 3,4-dihydroxyphenylalanine to dopachrome. Thus, these studies are in agreement with the original postulate, that 4-(2-carboxy-2-aminoethyl)-1,2-benzoquinone and leukodopachrome are the intermediates in the major pathway for dopachrome synthesis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Basidiomycota / enzymology
  • Dihydroxyphenylalanine / analogs & derivatives*
  • Dihydroxyphenylalanine / metabolism
  • Kinetics
  • Melanins / biosynthesis*
  • Monophenol Monooxygenase / metabolism
  • Oxidation-Reduction
  • Periodic Acid
  • Spectrophotometry
  • Spectrophotometry, Ultraviolet

Substances

  • Melanins
  • Periodic Acid
  • 6-hydroxydopa
  • Dihydroxyphenylalanine
  • Monophenol Monooxygenase