Purification and characterization of two pancreatic elastase isoforms from dogfish (Scyliorhinus canicula)

Two elastase isoforms were isolated from activated pancreatic extract of dogfish (Scyliorhinus canicula). The purification procedures for both elastases included ammonium sulfate fractionation, ion exchange on DEAE cellulose and Mono-QHR column followed by gel filtration on PL-GFS (HPLC) column. The two isoenzymes, EI and EII, exhibit a high activity toward the specific elastase substrate succinyl-(ala)3-p-nitroanilide (SANA) with different kinetic parameters at 37 degrees C. However, the two different enzymes have similar properties on the basis of pH, temperature, and molecular weight study. The activity of both variants was completely inhibited by elastatinal, phenylmethyl sulfonyl fluoride, (PMSF), diisopropyl fluorophosphate, (iPr2-FP), but less by p-chloromercuribenzoic acid (PCMB) and soybean trypsin inhibitor. EI and EII have similar amino acid composition; their amino-terminal sequences have 85% homology with human and rat elastase 2.