title: Partial purification and characterization of a double-stranded RNA-specific nuclease from human placenta.
abstract: A double-stranded RNA-specific nuclease (ds RNase) has been isolated and partially purified from human placenta by DEAE-cellulose and DNA-cellulose column chromatography. Denatured DNA-cellulose retained most of the single-stranded RNA-specific nuclease (ss RNase) activity, whereas the ds RNase came out in the void volume. N-ethylmaleimide at a concentration of 5 mM, selectively inhibited ds RNase activity by 60% under the conditions in which the ss RNase activity was inhibited to an extent of 7%. The ds RNase was specifically inhibited by Penicillium chrysogenum viral ds RNA and by ethidium bromide. The partially purified ds RNase showed requirements for Mg+ whereas Mn2+ and NH4+ ions were inhibitory. The DEAE-enzyme cleaved 32P-labelled 45S ribosomal precursor RNAs from Yoshida ascites sarcoma cells into species that had similar electrophoretic mobilities as the mature rRNAs.
mesh_terms: D000641:Ammonia / Q000378:metabolism; D004722:Endoribonucleases / Q000302:isolation & purification* / Q000378:metabolism; D005260:Female; D006801:Humans; D008274:Magnesium / Q000378:metabolism; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy
chemical_list: D000641:Ammonia; C033547:2'-5'-oligo(A)-dependent endonuclease; D004722:Endoribonucleases; D008274:Magnesium