GB2454672A — Chromogenic protease substrates

USPTO Abstract

A polypeptide comprising a chromogenic amino acid, wherein the chromogenic amino acid is flanked by at least one amino acid to the N- and C-termini, and wherein the amine group of the chromogenic amio acid has a pKa of less than 5, and the amino acid is capable of reacting with a conjugated aldehyde. The chromogenic amino acid may be p-aminobenzoic acid (pABA). A method of detecting a protease using such a polypeptide comprising: cleaving the polypeptide with a protease to create a fragment containing the chromogenic amino acid, reacting a conjugated aldehyde with the fragment to produce a coloured adduct and detecting the coloured adduct, the presence of the coloured adduct being indicative of the protease. A method of making such a polypeptide by synthesising an amino acid dimer comprising one chromogenic amino acid and incorporating the dimer into the remainder of the polypeptide. Also claimed is a synthetic polypeptide comprising at least one chromogenic amino acid.