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

DOI: 10.1039/C9OB00550A DOI Help

Authors: Jessica A. Hutchinson (University of Reading) , Ian W. Hamley (University of Reading) , Charlotte J. C. Edwards-gayle (University of Reading) , Valeria Castelletto (University of Reading) , Cristian Piras (University of Reading) , Rainer Cramer (University of Reading) , Radoslaw Kowalczyk (University of Reading) , Jani Seitsonen (Aalto University School of Science) , Janne Ruokolainen (Aalto University School of Science) , Robert P. Rambo (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Organic & Biomolecular Chemistry , VOL 26

State: Published (Approved)
Published: April 2019
Diamond Proposal Number(s): 17118 , 19754

Abstract: 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.

Subject Areas: Chemistry


Instruments: B21-High Throughput SAXS