Tyrosinase-induced cross-linking of tyrosine-containing peptides investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

✍ Scribed by Joong-Gu Jee; Sung-Jun Park; Hie-Joon Kim

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 83 KB
• Volume: 14
• Category: Article
• ISSN: 0951-4198
• DOI: 10.1002/1097-0231(20000830)14:16<1563::aid-rcm45>3.0.co;2-4

✦ Synopsis

Tyrosinase-induced oxidation of tyrosine is known to lead to melanin by cross-linking of 5,6dihydroxyindole (DHI) and indole-5,6-quinone intermediates. However, tyrosinase-induced cross-linking of tyrosine-containing peptides has not been reported. We observed tyrosinase-induced adducts of tyrosinecontaining peptides by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). MALDI-TOFMS was also used to observe tyrosine adducts at various levels of oxidation derived from acid hydrolysis of the peptide adducts. The rate of tyrosinase-induced browning of lys-tyr-lys was about half of that of tyrosine. These results indicate that tyrosinase-induced browning of tyrosine-containing peptides via direct oxidation and cross-linking of the benzene ring of the tyrosine residue occurs at a significant rate and needs to be considered in melanogenesis.