Environ Exp Biol (2016) 14: 83–90

Catalytic and kinetic properties of purified Eichhornia crassipes leaf peroxidase

Abstract

Peroxidase from Eichhornia crassipes leaf was purified 23.58 fold with 18.58% yield by means of (NH₄)₂SO₄ precipitation, ion exchange and Sephadex G-75 gel filtration chromatography. Optimum temperature and substrate-dependent pH optimum for enzyme activity were 40°C and pH 4.0, 9.0 and 6.0 for 2,2’-azino-bis-(3-ethylbenzthiazolin)-6-sulfonate (ABTS), guaiacol and pyrogallol, respectively. The enzyme had high pH stability and moderate thermal stability at temperatures up to 60°C; the activation energy of inactivation of the enzyme was ~122.29 kJ mol^–1. Temperature-denaturing and spontaneous recovery were shown to be time-dependent while Ca²⁺-enhanced recovery of the denatured enzyme was in a time-dependent manner. The enzyme showed preferential affinity for ABTS over guaiacol and pyrogallol with K_M values of 31.11, 21.91 and 6.45 mM respectively. It was reversibly inhibited by Pb²⁺, Hg²⁺ and EDTA while urea only caused loss of ~30.40% activity after 60 min of incubation. E. crassipes leaf peroxidase has potential use for broad range of applications.