LAUSR

Abstract We report the properties of peroxidase from red and white cultivars of kolanut, Cola nitida, for the purpose of providing information on suitability or otherwise of the enzyme for different biotechnological applications. Peroxidase is present in the crude extract of both cultivars with a specific activity of 52 ± 4 and 50 ± 7 units/mg protein for red and white nuts respectively. During purification the enzyme was separated into two isoforms with native molecular weight of 38.2 ± 1.8 kDa for white kolanut; 43.3 ± 1.5 kDa and 26 ± 1.8 kDa respectively for isoenzymes A and B of the red cultivar. Optimum temperature of all the isoforms of peroxidase from the two cultivars was 35 °C. Optimum pH for white cultivar enzyme was 4.5 and red cultivars had 5.0. All the isoforms were quite stable in 5 mM H2O2 concentrations or below. The catalytic efficiencies (kcat/Km) of all the purified proteins were between 105–107 M−1 s−1. Some of the isoforms were activated in water-miscible organic solvents. Kolanut peroxidase could be bonded to bovine serum albumin forming a higher molecular weight adduct. The study concluded that kolanut peroxidase possesses many physicochemical properties that make it suitable for application in biotechnology.