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

Hutchinson, J. A., Hamley, I. W. ORCID: https://orcid.org/0000-0002-4549-0926, Edwards-Gayle, C. J. C., Castelletto, V., Piras, C., Cramer, R. ORCID: https://orcid.org/0000-0002-8037-2511, Kowalczyk, R. ORCID: https://orcid.org/0000-0002-3926-6530, Seitsonen, J., Ruokolainen, J. and Rambo, R. P. (2019) Melanin production by tyrosinase activity on a tyrosine-rich peptide fragment and pH-dependent self-assembly of its lipidated analogue. Organic & Biomolecular Chemistry, 17. pp. 4543-4553. ISSN 1477-0520 doi: 10.1039/C9OB00550A

Abstract/Summary

We investigate the self-assembly of a palmitoylated (C16-chain at the N terminus) peptide fragment in comparison to the unlipidated peptide EELNRYY, a fragment of the gut hormone peptide PYY3–36. The lipopeptide C16-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.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/83379
Identification Number/DOI	10.1039/C9OB00550A
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Publisher	Royal Society of Chemistry
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