EXTRACTION AND PURIFICATION OF CYTOSINE DEAMINASE PRODUCED FROM Escherichia coli

	EXTRACTION AND PURIFICATION OF CYTOSINE DEAMINASE PRODUCED FROM Escherichia coli
Iraqi Journal of Biotechnology
Article 1, Volume 9, Issue 3, 2010, Pages 490-501
Abstract
The study involved isolation and characterization of E. coli from patient’s infected with diarrhea, in order to study the ability of the bacteria to produce cytosine deaminase (CD). The CD was extracted by destruction of cells using ultrasonic waves, the value of specific activity of crude extract was 5.3 unit/mg protein. Then the enzyme was purified in few steps including treatment of extract by heating at 60 oC for 30 min. The value of specific activity was 6.2 unit/mg protein, fold of purification was 1.2 times, and the yield was53.8 %. Then the enzyme was precipitated by using ammonium sulfate at 30-55% saturation percentage, the precipitate was dissolved in 0.5M potassium phosphate buffer. The value of specific activity was 10.8 unit/mg proteins, fold of purification was 2.0 times, and the yield was 3.59%. Then the enzyme solution was passed through DEAE-Cellulose column chromatography. The peaks of activity was collected and the value of specific activity was 189.9 unit/mg protein, fold of purification was 34.3 times, and the yield was 5.0%. The enzyme solution was concentrated and passed through Sepharose-6B gel-filteration and the value of specific activity was 302.0 unit/mg protein, fold purification 57.3 run, and yield was 2.1 %.
Keywords
Cytosine deaminase; Escherichia coli; Purification; Sepharose; DEAE; cellulose

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