الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 186 |  |  |
| | | from | 186 | | |
Abstract
- Pullulanase activity was investigated in cotyledons of some C3 plants, sunflower exhibited the highest activity. Pullulanase was induced in cotyledons of sunflower by JA, benzyladenine, coumarin, kinetin, zeatin and GA3. Pullulanase activity increased gradually by treating the enzyme extract with green, red and brown algae methanol extracts. α-aminolevulinic acid, Tween-60 and Tween-80 induced the enzyme activity. - Pullulanase was purified using schedule includes ammonium sulphate, phenyl sepharose, sephadex G-200 and hydroxyl apatite. - Thiol compounds such as DTT, 2-ME, cysteine and GSH increased pullulanase activity. Various metal cations on pullulanase activity were tested and Ca2+ and K+ exhibited the highest activity at all. Ca2+ increased pullulanase activity. The Km value was 1.34 mM and Vmax value was 34.8 mM/min. - The effect of adenosine compounds (AMP, ADP and ATP) on pullulanase activity from sunflower cotyledons was examined. -Chelating agents such as EDTA, EGTA, O-phenanthroline and α-ά-dipyridyl inactivated pullulanase, so pullulanase is a metallo enzyme. - Different polyols such as ethylene glycol, glycerol and sorbitol improved pullulanase activity and make it more stable under thermal conditions. Sarcosine and carbohydrates such as glucose, sucrose and maltose provide high protection against thermostability. - Tryptophanyl, tyrosyl and lysyl groups are essential for enzyme catalysis. - The enzyme was immobilized on silica gel 60, agar–agar, Ca-alginate and chitosan. Chitosan exhibited the best yield of immobilized pullulanase. The optimum temperature was 40 °C and 50 °C for free and chitosan-immobilized pullulanse, respectively. -The activation energies were found to be 2.37 K Jol mol-1 and 1.86 K Jol mol-1 for free and immobilized pullulanase, respectively. -The optimal Ph 6.0 and 8.0 for free and chitosan-immobilized pullulanase, respectively. The immobilized enzyme was expressed higher storage stability compared to the free enzyme and could be reused several times. Pullulanase is used in combinations with α-amylase and glucoamylase for production of glucose syrups as a biotechnological application.