PURPOSE: To prepare urease having a high Km value and good stability, by cultivating a strain belonging to the genus Bacillus in a nutrient culture medium.
CONSTITUTION: A bacterium UR-155 strain, separated from a soil in a thicket of assorted trees in NAGAIZUMI Town, SUNTO District, SHIZUOKA Prefecture, and belonging to the genus Bacillus is inoculated into an ordinary nutrient culture medium, and cultivated at 6W8 pH and 20W30°C for 1W4 days to give the aimed urease having the following properties: Action: Consumes one mole water from one mole urea to form 2 moles NH3 and one mole CO2. Optimal pH: 7.8W8.3. Optimal temperature: 35W40°C. pH stability: Stable at 8W10pH by treatment at 37°C for 30min. Temperature stability: Stable up to 45°C by treatment at 8 pH for 30min. Substrate specificity: Shown in Table 1. Inhibitors: Shown in Table 2. Km value: 4.5×10-2M (7.5 pH, phosphoric acid buffer solution). Molecular weight: About 440,000 (measured by the gel filtration method). Isoelectric point: About 5.0pH (measured by the fractionation method with a carrier "Ampholyte").
TAKIGUCHI TOSHIMITSU
ENDOU KENICHI
ARAI TAKEMITSU
TAKAYAMA KENICHIROU
MASUMIZU IZUMI
Next Patent: PREPARATION OF GRANULAR IMMOBILIZED MOLDED MATERIAL OF YEAST HAVING FERMENTING ABILITY OF ALCOHOL