摘要
从广东各地的热温泉(55—95℃)水样中,分离到200余株最适生长温度高于70℃的极端嗜热菌。其中一株编号为 HG25,具有耐热胞内 L-乳酸脱氢酶(L-Lactate dehydrogenase EC.1.1.1.27.,简称 LDH),有栖热菌属(Thermus)的特征,革兰氏阴性,无芽孢,好氧,不运动,产黄色素,最适生长温度为65—75℃,最高生长温度为85℃,最低为40℃,不水解淀粉,不从葡萄糖产酸,DNA 的 G+C 百分含量为65mol%,L-乳酸脱氢酶经硫酸铵分级沉淀、DEAE-纤维素柱层析作了初步提纯,比活提高7倍,LDH 还原丙酮酸反应的最适温度为60℃,最适pH为8.0,酶在70℃稳定,保温10分钟后,仍保留85%的原始酶活力。失活半寿期(t_(1/2))为85℃10分钟。
About 200 strians of extereme thermophilic
bacteria were isolated from hot springs in
Guandong province.A strian,HG25,was
found to produce thermostable intracellular L-
lactate dehydrogenase (EC.1.1.1.27).It has
the characteristic of Thermus sp..The cells
were gram-negative,nonsporulating,nonmo-
tile,arobic rods containing yellow pigment.
The optimum temperature for growth was be-
tween 65℃ to 75℃,the maximum 85℃,and
minimum 40℃.The generation time at the
optimum was about 80 min.Starch was not
hydrolized.Acid was not produced from
glucose.The G+C content in DNA was 62—
65mol%(T_m).As the properties of strian HG25
is similar to those of Thermus aquaticus and
T.thermophilus HB 8 belonging to the genus
Thermus.
The thermostable L-lactate dehydrogenase
was partially purified by ammonium sulfate
fractionation and DEAE-cellulose column
chromatography.For pyruvate reduction,the
optimum temperature of the enzyme was 60℃
and pH 8.0.After incubation in 0.1 mol/L
phosphate buffer pH 7.4 at 70℃ for 10min,
the enzyme retained about 85% of its original
activity.The half-live time (t_(1/2)) at 85℃ was
10 min.
出处
《微生物学报》
CAS
CSCD
北大核心
1991年第6期438-442,共5页
Acta Microbiologica Sinica
基金
国家自然科学基金
