ISP enzyme kinetics. A- Affinity of different synthetic chromogenic substrates (N-Benzoyl-DL-Arginine-β-Naphthylamide [BANA], N-Benzoyl-DL-Arginine-p-NA [BAPNA], N-Benzoyl-L-Arginine Ethyl Ester [BAEE], N-Benzoyl-Phe-Val-Arg-pNA [BPVANA], N-Benzoyl-L-Tyrosine-pNA [BTNA], N-Succinyl-L-Phe-pNA [SPNA], N-Succinyl-Ala-Ala-Ala-pNA [SAANA], N-CBZ-Gly-Gly-Leu-pNA [CGGLNA], Ile-Pro-Lys-pNA [IPLNA], N-Tosyl-Gly-Pro-Lys-pNA [TGPLNA], Val-Pro-Lys-pNA [VPLNA]) for the ISP1-ISP2 enzyme complex. The trypsin substrate BPVANA showed the greatest affinity to the enzyme complex. B- Enzyme inhibition data showing the affinity of different serine proteinase inhibitors to the ISP1-ISP2 enzyme complex. TSI, Gabexate and BABIM have a relatively high affinity for ISP enzyme, compared to Benzamidine.