Inhibitory studies of peroxidase from infected African eggplant (<i>Solanum aethiopicum</i>) fruit

Abstract

The effect of two parameters: inhibitors (potassium cyanide, salicylic acid and urea) and heat on peroxidase from the infected Solanum aethiopicum grown within the Nsukka Area of Enugu State, Nigeria was studied. The inhibitory and heat studies were carried out using standard procedures. The thermal stability of the enzyme was monitored using thermodynamic parameters after heating the enzyme over a temperature range of 30-70°C for 90 min. Potassium cyanide and salicylic acid and urea inhibited the enzyme in a concentration dependent manner. The inhibition of the enzyme by salicylic acid was an indication that the enzyme is a heme-protein. A high half-life of 64.78 mins was observed when the enzyme was heated at 50 °C for 90 mins. The free energy change (ΔG) values of 55.142, 58.731, 60.472, 60.227 and 64.296 KJ/mol and entropy (ΔS) values of -196.45, -179.07, -178.49, -195.66 and -195.43 were obtained. Similarly, low Z-value was obtained. The thermal stability results implied that high amount of energy was required to initiate the enzyme denaturation at the temperatures studied.

Keywords: Peroxidase, Solanum aethiopicum, bioenergetics, Inhibitory Studies, salicylic acid, potassium cyanide