Study on enzymes of industrial interest in digestive viscera: Greater amberjack (Seriola dumerili)

Objective:To investigate the presence of industrial enzymes (trypsin and chymotrypsin) as well as collagenolytic and fibrinolytic activities of the neglected processing waste of greater amberjackSeriola dumerili(S. dumerili). Methods: The investigations on trypsin, chymotrypsin, collagenolytic and fibrinolytic activities in residues in digestive viscera were performed. The enzymes trypsin and chymotrypsin were physicochemically characterized (including pH- and thermo-stabilities and sensitivity to metal ions and inhibitors). The kinetic parameters were also determined. Collagenolytic and fibrinolytic activities of the crude extract were also investigated. Results:The crude extract ofS. dumerili showed enzymatic activity of (1.4600 ± 0.0011 and (0.7100 ± 0.0079) IU/mg protein for trypsin and chymotrypsin, respectively. The optimal temperature and pH was 60°C and 9 for trypsin and 40°C and 8 for chymotrypsin. The main inhibitory ions were in the following order: Fe3+> Cu2+> Zn2+> Cd2+> Hg2+ (trypsin) and Hg2+> Fe3+> Zn2+> Cd2+> Mn2+(chymotrypsin). TLCK and benzamidine were the strongest inhibitors for both enzymes. The crude extract also presented collagenolytic activity [(42.44 ± 0.01) IU/mg] and fibrinolytic activity ((26.70 ± 0.05) IU/mL)Conclusions:The crude extract ofS. dumerili showed potential for reuse of its residues and to provide biomolecules of industrial interest like trypsin and to be a source of fibrinolytic enzymes.

Effect of ions on the activity of brain acetylcholinesterase from tropical ifsh

Objective:To investigate the effect of ions on brain acetylcholinesterase(AChE;EC 3.1.1.7)activities from economic important fish[pirarucu,Arapaima gigas;tambaqui,Colossoma macropomum;cobia,Rachycentron canadum(R.canadum)and Nile tilapia,Oreochromis niloticus(O.niloticus)]comparing with a commercial enzyme from electric eel[Electrophorus electricus(E.electricus)].Methods:Thein vitro exposure was performed at concentrations ranging from 0.001 to 10 mmol/L(except for ethylene diamine tetraacetic acid;up to 150 mmol/L).Inhibition kinetics onR.canadum andO.niloticus were also observed through four methods(Michaelis-Menten,Lineweaver-Burk,Dixon and Cornish-Bowden plots)in order to investigate the type of inhibition produced by some ions.Results:Hg^(2+),As^(3+),Cu^(2+),Zn^(2+),Cd^(2+)caused inhibition in all the species under study.Ca^(2+),Mg^(2+)and Mn^(2+)induced slight activation inR.canadum enzyme while Pb^(2+),Ba^(2+),Fe^(2+),Li+inhibited the AChE from some of the analyzed species.The lowest IC50 and Ki values were estimated forE.electricus AChE in presence of Hg^(2+),Pb^(2+),Zn^(2+).Under our experimental conditions,the results forR.canadum andO.niloticus,As^(3+),Cu^(2+),Cd^(2+),Pb^(2+)and Zn^(2+)showed a non-competitive/mixed-type inhibition,while Hg^(2+)inhibited the enzyme in a mixed/competitive-like manner.Conclusions:E.electricus AChE activity was affected by ten of fifteen ions under study showing that this enzyme could undergo interference by these ions when used as pesticide biosensor in environmental analysis.This hindrance would be less relevant for the crude extracts.