고온성 방선균으로부터 내열성 $alpha$-Amylase의 생산과 그 이용 가능성을 검토하기 위하여 토양시료로부터 $alpha$-Amylase 생산능력이 극히 우수한 구주를 분리하여 분리균의 몇가지 균학적 성질내지는 효소생산을 위한 배양조건을 조사하여 전보에 발표하였으며 본보에서는 공시방선균이 생산하는 $alpha$-Amylase의 효소학적 일반성질을 검토하여 다음과 같은 결과를 얻었다. 1) 본효소의 최적활성 pH는 6.5이었으며 최적변성온도는 55$^{circ}C$~$65^{circ}C$이었다. 2) 본효소의 안정 pH범위는 7.0~8.0에 위치 하였으며 3) 활성에 대한 금속 ion의 영향은 $Ca^{＋＋}$ 및 $Na^{＋＋}$ ion에 의하여 촉진되었으나 중금속 ion인 Fe$^{＋＋}$ Cu$^{＋＋}$ ion등은 현저히 조해함을 보였으며 열안정성에 대한 금속 ion의 효과는 $Ca^{＋＋}$ ion에 의해 증가했다. 4) 본 순소의 Km value는 2.17$ imes$$10^{-4}$g per $mell$이었으며 5) Activation energy는 12,000$pm$580 ㎈ per mole 이었다.
During the course of studies on the production and utilization of thermostable ${alpha}$-amylase from a thormophilic actinomycete species isolated from soil, partial characterization of the ${alpha}$-amylase has been (arried out. The optimum pH for the dextrinogenic activity of the enzyme was found to be 6.5 and the maximum reaction rate was achieved at a temperature range of 55$^{circ}$ to 65$^{circ}C$. Calcium ion was recognized to have a slight effect in activating the enzyme, while heavy metal salts especially ferrous and cupric ions showed a remarkable inhibition effect. The enzyme was best protected iron thermal denaturation at pH 8.0 with tris-HCI buffer；inactivation was rapid at higher or lower pH values. Furthermore, its thermal stability was greatly increased by calcium ion, particulary at the final concentration of 1${ imes}$10$^$－2/ mole in the reaction mixture. The Km value for the ${alpha}$-amylase was calculated to be 2.17${ imes}$10$^$－4/g per $mell$ and the energy of activation for the dextrinogenic reaction to be 12,000${pm}$580 ㎈ per mole.
