Synthesis of chromogenic substrates specific for human spleen fibrinolytic proteinase (SFP) and human leukocyte elastase (LE).

Abstract

Various peptide anilides were synthesized by a conventional method with the object of obtaining specific substrates for human spleen fibrinolytic proteinase (SFP) and human leukocyte elastase (LE) in order to compare the substrate specificity of SFP with that of LE. It was found that the P₁ Val compound among succinyl tripeptide p-nitroanilides (Suc-Tyr-Leu-X-pNA) exhibited the highest k_cat/K_m values for hydrolysis by SFP and LE, however, the tetrapeptide Suc-Ala-Tyr-Leu-Val-pNA [k_cat/K_m values (M^-1S^-1) for hydrolysis by SFP and LE : 84000 and 48000, respectively] was the preferred chromogenic substrate for SFP and LE because of its high solubility in the buffer and its moderate k_cat/K_m values. The substrate specificity of SFP was found to be similar to that of LE.