الفهرس 
Improving and extracting of enzymes from callus in barhee date palm (Phoenix dactylifera L.) In Egypt and Algeria
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Abstract
Date palm (Phoenix dactylifera L.) callus exposed easily to browning phenomenon which result from an increase of secondary metabolites So, it{u2019}s important to benefit from this negative phenomenon in the production of important enzymes (Pectin methylesterases (PME), Phenylalanine ammonia lyase (PAL), Peroxidase (POD), and Polyphenol oxidase (PPO) of callus. Fresh formatted date palm (cv. Barhee) callus was treated with different treatments and studied its effect on callus characteristics and crude enzymes activity. Crude enzymes were purified with different methods (ammonium sulfate, acetone, and ethanol) to study optimum pH, temperature, and enzymes kinetics on purified enzyme. The highest for (PME), (POD) and (PPO) specific activity was on treatment sucrose150g/L, and for (PAL) was on treatment L-glycine 400mg/L. Optimum pH for (PME) pH7.5, (PAL) pH8.5 (POD) and (PPO) pH6.5. Optimum temperature found at 400C for (PME) and (POD), at 500C for (PPO) and (PAL). Km and Vmax were recorded for citrus pectin, l-phenylalanine, guaiacol, H2O2, and catechol was (3.07 mg/reaction) (666.67 U.min-1), (0.51 mM/reaction) (212.76 U.min-1), (0.4 mM/reaction) (0.87 U.min-1), (0.24 mM/reaction) (0.44U.min-1) and (10.23 mM/reaction) (3333.33U.min-1) respectively. The obtained results showed that there is a close correlation between the increased activity of these enzymes (POD and PPO) and browning phenomenon, Stander tissue culture conditions (pH and temperature) didn{u2019}t meet the optimum conditions for these enzymes in spite of this POD and PPO under tissue culture conditions showed a high level of activity, PME showed an average level of activity and it could be improved while PAL showed a very low level of activity