Extraction, purification and characterization of L-Asparaginase from Withania somnifera ripe fruits

العناوين الأخرى

استخلاص و تنقية و توصيف إنزيم الأسباراجينيز من الثمار الناضجة لنبات (Withania Somnifera)‎

مقدم أطروحة جامعية

Majid, Abd al-Majid Zafir

مشرف أطروحة جامعية

Muhammad, Ali Sadiq

أعضاء اللجنة

Hashim, Abd al-Karim J.
Jabr, Muhammad A.
Shawkat, Muayyad Sabri

الجامعة

جامعة بغداد

الكلية

كلية العلوم

القسم الأكاديمي

قسم التقانة الإحيائية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2011

الملخص الإنجليزي

L-asparaginase (EC 3.5.1.1.) activity has been detected in crude extracts of medicinal plant Withania somnifera in leaves, ripe fruits and unripe fruits.

The enzyme activity was higher in the ripe fruits than other two parts.

Two types of L-asparaginase were detected in this study, potassium-dependant and potassium independent L-asparaginase, the optimization of extraction method was achieved to elevate the specific activity from 0.37 U/mg to 2.54 U/mg.

Lasparaginase has been purified from Withania somnifera fruits by two purification steps, Ion-Exchange Chromatography using DEAE-Cellulose and Gel Filtration Chromatography using Sephadex G-150, this two purification steps raised the specific activity from 1.73 U/mg in crude extract to 2.29 U/mg after Ion-Exchange and 10.5 U/mg after Gel Filtration, the purification fold was 1.32 after Ion-Exchange and 6.06 after Gel Filtration, the enzyme recovery was 56 % after two purification steps.

The results of enzyme purity detection by PAGE (polyacrylamide-gel electrophoresis) revealed dense bands along the gel with crude extract sample and only one clear band, at 4.5 cm from the top of the gel with purified enzyme.

Characterization results demonstrated that, the optimal pH ranges for activity and stability were pH 8 and pH 9 respectively, as well as the optimal temperatures for activity and stability were 50 ºC and 30 ºC respectively.

The amino acid analysis of the purified enzyme illustrated that, L-asparaginase is composed of 121 residues proline, 90 residues arginine, 88 residues aspartic acid, 74 residues glutamic acid, 35 residues alanine, 30 residues lysine, 29 residues therionine, 27 residues histidine, 25 residues serine, 23 residues leucine, 20 residues valine, 16 residues glysine, 14 residues isoleucine, 14 residues phenylalanine and 9 Summary residues methionine, according to this composition, the number of polar amino acids was 379 residues, while the number of non-polar amino acids was 236 residues, so the L-asparaginase is hydrophilic enzyme, in addition to that the number of positive charged amino acids was 120 residues, negative charged amino acids was 162 residues, so the net charge of the enzyme at pH 7 is negative and finally.

التخصصات الرئيسية

النبات

الموضوعات

• المشروبات الكحولية
• الأحماض الأمينية
• المركبات العطرية

عدد الصفحات

77

قائمة المحتويات

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-600656