Melanin production by tyrosinase activity on a tyrosine-rich peptide fragment and pH-dependent self-assembly of its lipidated analogue

Research output: Contribution to journalArticleScientificpeer-review


  • Jessica A. Hutchinson
  • Ian W. Hamley
  • Charlotte J.C. Edwards-Gayle
  • Valeria Castelletto
  • Cristian Piras
  • Rainer Cramer
  • Radoslaw Kowalczyk
  • Jani Seitsonen
  • Janne Ruokolainen
  • Robert P. Rambo

Research units

  • University of Reading
  • Diamond Light Source


We investigate the self-assembly of a palmitoylated (C 16 -chain at the N terminus) peptide fragment in comparison to the unlipidated peptide EELNRYY, a fragment of the gut hormone peptide PYY 3-36 . The lipopeptide C 16 -EELNRYY shows remarkable pH-dependent self-assembly above measured critical aggregation concentrations, forming fibrils at pH 7, but micelles at pH 10. The parent peptide does not show self-assembly behaviour. The lipopeptide forms hydrogels at sufficiently high concentration at pH 7, the dynamic mechanical properties of which were measured. We also show that the tyrosine functionality at the C terminus of EELNRYY can be used to enzymatically produce the pigment melanin. The enzyme tyrosinase oxidises tyrosine into 3,4-dihydroxyphenylalanine (DOPA), DOPA-quinone and further products, eventually forming eumelanin. This is a mechanism of photo-protection in the skin, for this reason controlling tyrosinase activity is a major target for skin care applications and EELNRYY has potential to be developed for such uses.


Original languageEnglish
Pages (from-to)4543-4553
Number of pages11
Issue number18
Publication statusPublished - 14 May 2019
MoE publication typeA1 Journal article-refereed

ID: 34095066