Studies on the Exo-maltotetraohydrolase of Pseudomonas stutzeri IAM 12097 -Part II. Characteristics of Exo-maltotetraohydrolase-

Pseudomonas stutzeri IAM 12097의 exo-maltotetraohydrolase에 관한 연구(硏究) -제2보(第二報). Exo-maltotetraohydrolase의 특성(特性)-

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, $pH6.0{\sim}10.5\;and\;45{\sim}50^{\circ}C$. The enzyme was stable below $40^{\circ}C$ and was rapidly inactivated above $55^{\circ}C$. This enzyme was inactivated completely by $Ag^+,\; Hg^{++},\;I_2$ and ${\beta}-cycoldextrin$, and slightly by EDTA, ${\rho}-CMB$ and IAA. Michaelis constant(Km) of this enzyme toward soluble starch, amylose and amylopectin were 7.70mg/ml, 6.17mg/ml, 5.56mg/ml, respectively.

Pseudomonas stutzeri IAM 12097이 생산(生産)하는 Exo-maltotetraohydrolase의 gel filtration에 의하여 추정(推定)된 분자량(分子量)은 60,000이었고, SDS-polyacrylamide gel electrophoresis에 의하여 추정(推定)된 분자량(分子量)은 63,000이었으며 등전점(等電點)은 PH 4.8이었다. 최적(最適)pH는 6.6, PH안정(安定)범위는 $6.0{\sim}10.5$, 최적온도(最適溫度)는 $45{\sim}50^{\circ}C,\;40^{\circ}C$이하(以下)에서는 안정(安定)하였으며, $55^{\circ}C$이상(以上)에서는 급격하게 불활성화(不活性化)되었다. 본효소(本酵素)는 $Ag^+,\; Hg^{++},\;I_2,\;{\beta}-cycoldextrin$에 의하여 완전(完全)히 저해(沮害)되었고 EDTA, ${\rho}-CMB$, IAA에 의하여 약간 저해(沮害)되었다. soluble starch, amylopectin, amylose에 대(對)한 Michaelis constant(Km)는 각각(各各) 7.70mg/ml, 6.17mg/ml, 5.56mg/ml이었다.