Synthesis of fluorescent peptidyl thioneamides and the assay of papain in the presence of trypsin

摘要: Abstract Fluorescent peptidyl thioneamides are synthesized for the first time. The carbonyl oxygen of scissile amide bond substrates was replaced by a sulfur atom. proteolytic activities trypsin and papain were measured against 5-(benzyloxycarbonyllysylthioamido)-isophthalic acid dimethyl ester (Z-Lys-ψ[CS]-AIE) 5-(benzyloxycarbonylphenylalanylarginylthioamido)-isophthalic (Z-Phe-Arg-ψ[CS]-AIE) compared to corresponding oxyamides. Kinetic constants measured. With thioneamide substrates, no tryptic hydrolysis observed. Papain, on other hand, hydrolyzed both oxy thioneamides. K m values shown be slightly lower than oxyamides, but efficiency overall catalytic activity off set turnover number thio derivatives. present synthetic substrate technology, selective detection cysteine proteases in presence serine is difficult. reported here alone trypsin.