Isolation of a trypsin-like enzyme from Piaractus mesopotamicus (Pacú)

Abstract

Piaractus mesopotamicus (pacú) is an omnivorous fish endemic of Paraguay-Paran¨¢ river basin, incorporated to the aquaculture production system in the northern region of Argentina. Fish viscera are a potential source of digestive enzymes, especially proteases. An interesting alternative to convert the fish processing wastes into useful products of higher value is the isolation of trypsin, one of the major digestive enzymes with potential industrial applications. This enzyme is currently marketed by its applications in food industry, as additive in laundry detergents, in cell culture technique and in the pharmacology area where is prescribed for several treatments (inflammatory edema associated with post-surgical wounds, traumatic injuries, rhinitis, sinusitis, etcetera). In this work we applied affinity chromatography on Benzamidine Sepharose column to isolate a tripsin-like protein from P. mesopotamicus processing waste. Pyloric caeca from pacú was disaggregated and homogenized in saline buffer (pH 7.8). After centrifugation, supernatant was applied to the affinity column equilibrated in Tris buffer (pH 7.8). The adsorbed material was eluted with low pH buffers, 4.5 and 3.2. The eluents were monitored at 280 nm for proteins. Trypsin activity was measured by the change in absorbance at 410 nm using N-¦Á-benzoyl-DL-arginine-p-nitroanalide (BApNA) as substrate. Fractions collected at pH 3.2 which exhibited trypsin activity were pooled, dialyzed and lyophilized. SDS-PAGE showed a single band compatible with fish trypsins. Isolated protease was active in a wide range of temperature (0-75°C) and highest activity was found at 45°C. At 75°C, about 50% of maximum activity was retained, a 20% higher than commercial porcine trypsin. This is an attractive property that allows use it as laundry detergent additive. This single step method is viable for isolation of trypsin-like enzyme from piloryc caeca of pacú with attractive features applicable on industry.