Abstract
The amino acid sequence of elastase inhibitor, AFLEI, isolated from Aspergillus flavus was determined by the Edman sequencing procedure of peptides derived from digests utilizing clostripain. A molecular weight of 7,525.8 was observed by TOF-MS. AFLEI contained 68 amino acid residues and has a calculated molecular weight of 7,526.2. The search for amino acid homology with other proteins demonstrated that amino acid residues 1 to 51 of AFLEI are 100% identical to residues 20 to 70 of the hypothetical protein Afu3g14940.
The Michaelis constant (Km) for succinyl L-alanyl- L-alanyl- L-alanyl p-nitroanilide (STANA) , and inhibition constant (Ki) , for elastase of AFLEI, were found to be 6.7×102μM and 4.0×10-2μM, respectively.
Inhibitory activity was compared with six protease inhibitors (ulinastatin, nafamostat mesilate, sivelestat sodium hydrate, gabexate mesilate, elastatinal and elafin) . The other six protease inhibitors demonstrated very weak inhibitory activity by comparison with AFLEI.
