TITLE	Isolation and characterization of a group III isozyme of acid phosphatase from rice plants
AUTHOR	S. C. Tso Department of Botany, National Taiwan University, Taipei, Taiwan, Republic of China Y. R. Chen Department of Botany, National Taiwan University, Taipei, Taiwan, Republic of China
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ABSTRACT	The acid phosphatases (EC 3. 1. 3. 2.) of rice seedlings consisted of four groups of isozymes. The group III isozyme was purified through ammonium sulfate, DEAE-Sepharose, Con A-Sepharose, and chromatofocusing. A 198-fold enhancement of activity was attained. This isozyme showed only one band in native-polyacryamide gel electrophoresis. However, gel filtration revealed two peaks of enzyme activity. Their molecular weights were 130 kDa and 100 kDa. The purified isozyme showed a pH optimum of 5. Its Km for p-nitrophenyl phosphate (p-NPP) hydrolysis was 0.33 mM. Its activity was inhibited non-competitively by sodium fluoride. Mercuric chloride, sodium molybdate, and copper sulfate strongly inhibited the enzyme activity. The isozyme actively hydrolyzed adenosine triphosphate and p-NPP, and partially utilized fructose-1,6-diphosphate. It did not utilize fructose-6-phosphate, glucose-1-phosphate, glucose-6-phosphate, glycerophosphate, or adenosine monophosphate.
KEYWORD	Acid phosphatase; Enzyme purification; Isozyme; Oryza sativa;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 38 Number 4 October 1997, page 245-250, 6 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China