CALOTROPIS PROCERA” ENZYMES II–EXTRACTION, PARTIAL PURIFICATION AND CHARACTERIZATION     OF PEROXIDASE FROM CALOTROPIS PROCERA

A. Shakir, K.

	CALOTROPIS PROCERA” ENZYMES II–EXTRACTION, PARTIAL PURIFICATION AND CHARACTERIZATION OF PEROXIDASE FROM CALOTROPIS PROCERA
IRAQ JOURNAL OF AGRICULTURE
Article 1, Volume 10, Issue 1, 2005, Pages 0-0
Author
K. A. Shakir
Abstract
Three different solutions [ 1- distilled water, 2- potassium phosphate buffer (0.2 M), pH7 and 3- sodium chloride (6%) + boric acid (2%) ] were used separately to extract peroxidase from Calotropis procera leaves and stems at 4ْ C. The specific activity of enzyme extracted by solution (No. 3) was the highest, and considered as the best extraction solution. The enzyme was precipitated by gradual addition of ammonium sulphate to final saturation of 65%. The precipitate was dialyzed against distilled water, lyophilized and then applied on a column of sephacryl S-200 (60 x 1.5cm) for partial purification. The purification folds, enzyme yield and specific activity were 79.05%, 2.8 and 21502.59 respectively. The molecular weight of partially purified enzyme was 55.590 kda as determined by gel filtration chromatography and the carbohydrates content was 14.4%. The optimum temperature for enzyme activity was 55ºC, and the enzyme was most stable at 30-55ºC over 10 min. incubation. The enzyme showed maximum activity at pH 5.5 and it retained more than 90% of original activity over 10 min. incubation at pH 5. While it lost more than 90% of the original activity at pH 8.5 over the same incubation period. The activation energy for conversion of substrate to product was 30.702KJ.

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