Thermophilic actinomyces producing extracellular protease was isolated from soil sample in Jeju province, Korea, and was named as Thermoactinomyces CS707. Culture broth of Thermoactinomyces CS707 showed the highest protease activity at late exponentia...
Thermophilic actinomyces producing extracellular protease was isolated from soil sample in Jeju province, Korea, and was named as Thermoactinomyces CS707. Culture broth of Thermoactinomyces CS707 showed the highest protease activity at late exponential growth phase when grown in OSYM medium(Oatmeal 2.0%, Dried yeast 1.0%, Soybeen meal 1.0%, Mannitol 1.0%, pH 8.3) at 48℃, 180rpm. Three forms of protease, TA-1, TA-2 and TA-3, were isolated through ammonium sulfate fractionation, Ultrogel AcA 34 column chromatography and DEAE-Trisacryl column chromatography. The optimum temperature for the activities of pretense TA-1, TA-2 and TA-3 were 55℃ , 65℃ and 65℃, respectively. About 50% of the original pretense activities(TA-1, TA-2 and TA-3) remained after being treated at 60℃ for 30min. The optimum pH values of protease TA-1, TA-2 and TA-3 were 7.5, 6.5 and 10.0, respectively. Protease TA-1, TA-2 and TA-3 were stable in the pH range of 6~ll.5, 4~9 and 5~11, respectively. The activity of protease TA-1 was Inhibited by Cu^(2+), SDS, metal chelators EDTA and EGTA, and phenylmethylsulfonylfluride(PMSF). The activity of protease TA-2 was inhibited by Cu^(2+), Ni^(2+) and PMSF, Whereas the metal chelators EDTA and EGTA did not affect the enzyme activity of TA-2. The activity of protease TA-3 was inhibited by SDS, EDTA, EGTA and PMSF.