PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

This study was conducted to purify and characterize the chitinase enzyme from several wheat cultivars induced by the fungus Trichoderma longibrachiatum T1. The results recorded that the highest effect of induction of chitinase was for wheat cultivar Iba 99 as it reached 1.77 units / ml and controlled treatment for the same variety 0.61 units / ml, followed by the cultivar Abu Ghraib 1.72 units / ml and controlled treatment 0.62 units / ml. The lowest effect of Rabia cultivar was 1.36 units / ml and controlled treatment 0.48 units / ml. The enzyme was purified from the induced Iba 99. The purification steps included sedimentation with 80% ammonium sulfate salt, then DEAE - Cellulose Ion exchange chromatography and Sephadex G-100 gel filtration chromatography, the specific activity after the last step was 43.13 units / mg protein, the number of purification times was 70.22 times, and the enzyme yield was 72.47%. Then, the chitinase enzyme was described, as the results showed that the value of the Km and the maximum velocity Vmax were 12.65 mg / ml and 6.95 u / ml, respectively. The pH numbers 5 and 6 were optimum for the activity of the chitinase enzyme. Whereas, the pH range for stability was 5 and 6 for the chitinase enzyme. The chitinase enzyme showed thermal stability between 10 and 20º C for one hour. The optimum temperature for the enzyme’s activity was 30 and 40 C. The molecular weight of the purified enzyme was 30.2 KDa.