الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 131 |  |  |
| | | from | 131 | | |
Abstract
L-arginine is one of the most functionally diverse amino acids in living cells. Enzyme immobilization can help to enable applications of enzymes in various conditions such as, pH, chemical solvents, temperature and high substrate concentrations.This thesis aimed to isolate L-arginase from fenugreek plant, purify it, and immobilize it and studying its biochemical characteristics. The results of this current study can be summarized as follows : 1-L-arginase was isolated and purified using ammonium sulphate, diethylaminoethyl acetate and Sephadex G-200. The purified enzyme expressed specific activity of 61 units mg-1 protein with 103-fold. 2-The enzyme was immobilized on silica gel, Ca-alginate and chitosan. Ca-alginate was the best support for enzyme immobilization and the immobilization efficiency (%) values were 56.75%, 92.7% and 77.4 %, respectively for using the three compounds. 3-Phytohormones including benzylaminopurine, indoleacetic acid and gibberellic acid activated the free and immobilized L-arginase and gibberellic acid was the most activator. 4-The five tested reagents of the active groups namely : butandione, dansyl chloride, N-bromosuccinimide, N-ethylmaleimide and N-acetylimidazole inhibited the activity of free and immobilized enzymes on chitosan and alginate. The inhibition of the immobilized enzyme on alginate and chitosan was lower than that of the free L-arginase. This inhibition reveals the necessity of arginyl, lysyl, tryptophanyl, sulfhydryl and tyrosyl residues for L-arginase catalysis. 5-L-arginase expressed toxic effect against liver cancer (Hep-G2) cell line. In this regard, this toxic effect supported by the changes in the morphological features of the cancer cells. However, the normal cells were less affected.