Min J J, Zassenhaus H P
Department of Microbiology, St. Louis University Medical Center, Missouri 63104.
SAAS Bull Biochem Biotechnol. 1991 Jan;4:1-5.
We have purified and characterized a novel exoribonuclease that was isolated from the mitochondria of Saccharomyces cerevisiae. The enzyme degraded RNA in a 3' to 5' direction and was dependent on nucleotide triphosphates for activity. All eight of the standard ribo- and deoxyribonucleotide triphosphates supported activity with an apparent Km ranging from 20 to 90 uM. The enzyme also exhibited an RNA-dependent ATPase activity. Evidence suggests that in vivo the enzyme may associate with mitochondrial factors which can alleviate the dependence on nucleotide triphosphates for enzymatic activity. A model is discussed for the role of the enzyme in regulating the turnover of mitochondrial RNAs.
我们已经纯化并鉴定了一种从酿酒酵母线粒体中分离出的新型外切核糖核酸酶。该酶以3'到5'的方向降解RNA，其活性依赖于三磷酸核苷酸。所有八种标准的核糖和脱氧核糖三磷酸核苷酸都支持其活性，表观Km值范围为20至90μM。该酶还表现出RNA依赖性ATPase活性。有证据表明，在体内该酶可能与线粒体因子结合，这些因子可以减轻酶活性对三磷酸核苷酸的依赖性。本文讨论了该酶在调节线粒体RNA周转中的作用模型。
