Patent ID: 8216800

Claim:
An enzyme substrate for detecting peptidase activity of formula (I) below: in which: X is S, NX1, or O; R1 is nothing or is Cl, Br, F, I, OH, or an alkyl, aryl or carboxyl group; R2 is nothing or is Cl, O—CH 2 —O, O—CH 3 , F, diethylenediamine-CH 3 , NR3R4, Br, I, OH, an alkyl, aryl or carboxyl group, NO 2 , or X1 is H, C 2 H 4 Ph, OH, an alkyl group, or an aryl group; R3 and R4 are independently H or an alkyl group containing from 1 to 4 carbon atoms; and P is a peptide.