Characterization of digestive acidic and alkaline proteolytic enzyme (Proteases) from the visceral waste of fringed-lipped peninsula carp, Labeo fimbriatus (Bloch, 1795)

摘要

Acidic and alkaline proteases from visceral waste of Labeo fimbriatus (Bloch, 1795) were isolated, partiallypurified by ammonium sulphate precipitation followed by dialysis, their kinetics and characteristics studied. The crude enzymewas partially purified and its molecular weight was studied. The enzyme showed highest activity and purification-fold whenprecipitated at 40–60% ammonium sulfate. The purification fold increased from 1.23 to 2.49 and 1.17 to 1.51 in acidic andalkaline protease respectively along the purification steps. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) showed a molecular weight of 15-35 kDa and 25-63 kDa respectively in acidic and alkaline proteases. The pH andtemperature optima for acidic and alkaline proteases were 3 and 10, at 40°C and 60°C, respectively. The acidic and alkalineprotease activity was decreased by 40% and 60%, when incubated at 90°C for 30 min. Degree of hydrolysis (DH) of theproteases on muscle protein increased with increase of enzyme concentrations. The study showed that proteases from Fringedlipped carp visceral waste of could find use in applications, where maximum activity at moderate temperature is desired.