ISSN: 2577-4050
Authors: Silva ES, Zanandrea ACV, Cunha Bastos VLF, Bastos FF* and Cunha Bastos J
Enzymatic biomarkers can be effective tools for monitoring the health of aquatic organisms exposed to xenobiotics. The use of sample blood is beneficial to preservation, since it allows evaluations without the euthanasia of the animal, preserving the fauna and the balance of the ecosystem. Nevertheless, it is previously necessary to understand the kinetics of the enzymes and to determine their basal activity levels for the proper choice of the enzyme to be used for biomarking. The best assay conditions of carboxylesterase activity (CaE) present in the serum of four different species of neotropical fish were established and their activities were compared with other blood esterases. Also, the CaE were measured at summer and winter to verify possible seasonal changes. The CaE was assayed with the substrate para-nitrophenylacetate (p-NPA) by the appearance of product in one minute reaction. The dourado CaE had a KM and Vmax value similar to that of pacu, but the curimbatá showed the best catalytic efficiency to degrade p-NPA. In piauçu the activity of serum CaE is not as efficient when compared to the other species. Dourado, pacu and curimbatá have higher CaE than cholinesterase activity, distinct of piauçu. The CaE of pacu serum decreases in the winter. Thus, it is shown to be important to establish the level of activity of each esterase per species and to verify if seasonal variation may influence the analysis in the monitoring of enzymatic biomarkers.
Keywords: Carboxylesterase; Cholinesterase; Enzymes; Blood
