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KMID : 1007519960050030249
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Food Science and Biotechnology
1996 Volume.5 No. 3 p.249 ~ p.253
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Cloning and Expression of an Amylase Gene from Streptomyces Albus KSM - 35 in Escherichia coli
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Kim, Young Bae
Lee, Sung Taik/Cha, Jin/Rhim, Seong Lyul/Lee, Jae Woo/Yang, Sung Jun/Hong, Sung Yong
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Abstract
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The gene encoding amylase from Streptomyces albus KSM35 was cloned and expressed in E. coli TG1 using the pBGS18 plasmid as a cloning vector. The recombinant plasmid, pSJ1, contained a 5.7 kb BamHI fragment originated from S. albus KSM-35 chromosomal DNA. The pSJ1-transformed E. coli TG 1 exported the enzyme into the periplasmic space and the culture medium. The amylase expressed by E. coli had the same molecular mass (50 kDa) as that expressed by the parent strain, Streptomyces. The optimum temperature and pH of the cloned amylase were 50℃∼60℃ and 6.0, respectively. The cloned amylase was stable at 50℃ or below, in the presence of 10 mM CaCl₂, up to 70℃. In studies of amylase activity, maltotetraose was detected as the major product during the initial stages of starch hydrolysis. Maltotriose and maltose were also found in the extended reactions.
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