The other Topa: Formation of 3,4,5-trihydroxyphenylaianine in peptides
The other Topa: Formation of 3,4,5-trihydroxyphenylaianine in peptides
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DOI：
10.1006/abio.2002.5690
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发表时间：
2002-07-01
影响因子：
2.9
通讯作者：
Waite, JH
中科院分区：
文献类型：
--
作者：
Burzio, LA;Waite, JH
Hydroxylation of peptidyl-3,4-dihydroxyphenyl-L-alanine (Dopa) was observed during tyrosinase incubation of a decapeptide related to the mussel adhesive protein mefp1. The reaction was carried out at high enzyme concentrations (700 units tyrosinase/mumol of tyrosine). The hydroxylation of tyrosines in the decapeptide proceeds sequentially. First, Tyr-9 is hydroxylated to Dopa, followed by hydroxylation of Tyr-5; finally, Dopa-9 is hydroxylated to Topa. Topa was identified as 3,4,5-trihydroxyphenylalanine (3,4,5-Topa) by comparison to known standards using amino acid analysis, derivatization with phenylisothiocyanate in combination with Edman sequencing, and matrix-assisted laser desorption mass spectrometry with time-of-flight. Two other peptides, not related to mussel proteins, were also found to form peptidyl-Topa upon incubation with tyrosinase. Although 3,4,5-Topa has been reported in the primary sequence of several peptides, its formation in vitro from tyrosine-containing peptides is novel. The formation of Topa would appear to be a function of tyrosinase rather than the nucleophilic addition of water to dopaquinone. (C) 2002 Elsevier Science (USA).
