The invention relates to chromogenic compounds and the use thereof for the determination of enzymes of the family of carboxypeptidases N and carboxypeptidases U. The above is more specifically a compound of formula (I) in which A=(1), (2), (3), (4) or (5), R1, R2=H, --CH.sub.3, --CH(CH.sub.3).sub.2, --OCH.sub.3, --Cl,--CF.sub.3,--OCF.sub.3,--SCH.sub.3, R.sub.3=an amino acid group which may be hydrolysed by a carboxypeptidase A and R.sub.4=a basic amino acid group. ##STR00001##