Dual enzymatic activities of potato patatin: esterase and lipase characterization

Abstract

The purified E.coil-derived patatin is an enzyme with a molecular mass of 40 kDa, it displayed optimal esterase activity (against p-Nitrophenyl acetate, p-NPC₂) at 37 °C and a pH of 9.0 for 25 min. Its enzymatic activity was stable at pH 4.0–9.0 and could retain about 65.8% of its activity at 90 °C for 1 h. The residual activity remained over 80% in 4 weeks’ duration when patatin was freeze-dried or stored in a buffer solution of -80 to 25 °C, the residual activity remained over 80% for 4 weeks. Patatin’s enzymatic hydrolysis ability against p-NPC₂ was enhanced in the presence of K⁺, Mg²⁺, Al³⁺. Most organic solvents had no significant effects on its activity except ethyl acetate. Patatin showed broad specificity to substrates of different carbon chain lengths (C₂-C₁₆), of which the highest was against short carbon chains (C₂-C₄), with the lowest K_m of 1.01 mM and the highest V_max of 49.75 mmol/L·min to p-NPC₂. The patatin also possessed remarkable lipase activity in hydrolyzing oils and high selectivity to animal fats. These results suggested that the recombinant patatin has promising marketable potential in the hydrolysis of important ester or lipid in food, pharmaceutical, biochemical, and biological interests due to its broad substrate specificity and high stability.