Characterization of Phenoloxidase in The Red Palm Weevil; Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) (Olivier) Using Catechol Substrate

Phenoloxidases (EC.1.14.18.1) are implicated in the immunity of insects toward microorganisms, so oxidative enzymes such as phenoloxidases (PO) from 7th instar larvae red palm weevil; Rhynchophorus ferrugineus (Oliv.) was partially isolated to characterize its activity using catechol a substrate. The mitochondrial fraction larval homogenate used enzyme source for partial kinetic studies.Enzyme catalysis directly proportional crude protein conc. up 200 ug contained 1 ml reaction mixture. Michaelis-Menten kinetics PO evaluated by constructing Lineweaver Burk double reciprocal plot. Michaelis constant (Km) was, 3.45 X10-4 M and maximum velocity (V max) 344.8 O.D.min-1 mg protein-1. Effect pH, temperature substrate concentration on tested. Generally, each variable chosen while other conditions were at optimum found primarily. Reaction rate optimal 10-1 N catechol, neutral medium (pH 7) 40 C. kept most when incubated 60 C 15 min before initiation. efficiently catalyze catechol. Results present study may probably offer fundamental anchor future alternative strategies controlling R. via obstructing innate