TITLE	Purification and properties of fatty acid esterases from yam (Dioscorea batatas Decne) tuber
AUTHOR	Wen-Chi Hou Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan Hsien-Jung Chen Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan Chung-Fang Chang Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan Yaw-Huei Lin Institute of Botany, Academia Sinica, Nankang, Taipei 115, Taiwan
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ABSTRACT	Using b-naphthyl myristate (C14 fatty acid ester) as a screening substrate, we purified fatty acid esterases (FAEs) from yam (Dioscorea batatas Decne) tuber. Two FAE fractions (named FAE I and FAE II) were obtained after DE-52 ion exchange chromatography and Sephadex G-75 gel filtration purification steps, and then further purified by Con A Sepharose 4B affinity chromatography. FAE I and II fractions contained the same three protein bands about 50-64 kDa corresponding to esterase activity bands on SDS-PAGE gels. Among b-naphthyl esters determined at pH 4.0, 5.0 and 6.0 the best substrate for both FAE fractions was a C10-containing one with a maximum pH at 5.0. The Km and Vmax for b-naphthyl caprate (C10 fatty acid ester) of FAE I and II at 37°C, pH 5.0 were 0.338 and 0.959 mM; 0.405 and 0.585 nmole b-naphthol/min µg protein, respectively. FAE activity was stable below 50°C and lost completely above 65°C.
KEYWORD	Dioscorea batatas Decne; Fatty acid esterase (FAE); b-naphthyl caprate; b-naphthyl myristate; purification;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 40 Number 4 October 1999, page 305-310, 6 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China