title: Phenylhydrazide as an enzyme-labile protecting group in peptide synthesis.
abstract: The enzymatic cleavage of amino acid phenylhydrazides with the enzyme tyrosinase (EC 1.14.18.1) offers a new, mild, and selective method for C-terminal deprotection of peptides. The advantages of the described methodology are the very mild oxidative removal of the protecting group at room temperature and pH 7, a high chemo- and regioselectivity, and the availability of the biocatalyst. Even in oxygen-saturated solution, the oxidation of sensitive methionine residues was not observed. These features make the methodology suitable for the synthesis of sensitive peptide conjugates. Mechanistic data suggest that the hydrolysis of the oxidized adducts proceeds by a free-radical mechanism.
mesh_terms: D000363:Agaricales / Q000201:enzymology; D000596:Amino Acids / Q000737:chemistry*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D042845:Laccase; D008715:Methionine / Q000737:chemistry; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis*; D010659:Phenylhydrazines / Q000737:chemistry*; D013696:Temperature
chemical_list: D000596:Amino Acids; D010455:Peptides; D010659:Phenylhydrazines; C030299:phenylhydrazine; D008715:Methionine; D010088:Oxidoreductases; D042845:Laccase; D014442:Monophenol Monooxygenase; D010100:Oxygen