Four non-specific acid phosphatases designated BLsAP1, BLsAP2, RLsAP1 and RLsAP2 have been previously isolated from edible seeds of Lagenaria siceraria, an oleaginous cucurbit widely distributed and prized in both rural and urban areas in Sub-Saharan Africa. In this study, we investigate on the kinetic and thermodynamic characteristics of these biocatalysts in order to evaluate their thermostability. Thermal inactivation was performed in the temperature range of 55 to 80 °C from 5 to 60 min. Results revealed that thermal inactivation of studied acid phosphatases follows first order kinetics. At their optimum temperatures, these enzymes showed high half-lives ranging from 169.06, to 495.10 min and D values from 561.71 to 1645.03 min. Moreover, they exhibited high activation energies (from 155.08 to 200.55 kJ/mol) and average enthalpy values (from 152.23 to 197.74 kJ.mol-1) suggesting their good thermostability. The comparison of all these values revealed that the two acid phosphatases (RLsAP1 and RLsAP2) from the round-fruited cultivar of Lagenaria siceraria showed better thermal stability than those (BLsAP1 and BLsAP2) from the blocky-fruited cultivar.
Key words: Acid phosphatases, thermodynamic, characterization, thermal stability, Lagenaria siceraria, Cucurbitaceae edible seeds
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