Molecular weight of Exo-maltotetraohydrolase produced by Pseudomonas stutzeri IAM 12097 was estimated to be approrimately 63,000 and 60,000 with SDS-polyacrylamide gel electrophoresis and Sephadex-G-100 gel filtration, respectively. The isoelectric point was appeared to be pH 4.8. Optimum pH, the stable pH range and optimum temperature of this enzyme were pH 6.6, pH 6.0¡10.5 and 45¡50¡É. The enzyme was stable below 40¡É and was rapidly inactivated above 55¡É. This enzyme was inactivated completely by Ag^+, Hg^(++), I©ü and ¥â-cycoldextrin, and slightly by EDTA, ¥ñ-CMB and IAA. Michaelis constant(Km) of this enzyme toward soluble starch, amylose and amylopectin were 7.70§·/§¢, 6.17§·/§¢, 5.56§·/§¢, respectively.
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