Characterization of a novel NTP-dependent 3' exoribonuclease from yeast mitochondria.
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.
Department of Microbiology, St. Louis University Medical Center, Missouri 63104.
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JJ
Min
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Zassenhaus
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D003570:Cytidine Triphosphate / Q000494:pharmacology; D005095:Exoribonucleases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology*; D008970:Molecular Weight; D009711:Nucleotides / Q000494:pharmacology*; D012313:RNA / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D009711:Nucleotides; D012313:RNA; D003570:Cytidine Triphosphate; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D005095:Exoribonucleases; D000251:Adenosine Triphosphatases