title: Purification and characterization of an endoribonuclease from nucleoplasm and nucleoli of HeLa cells.
abstract: An endoribonuclease has been isolated from HeLa cell nuclei. Approximately 70% of the enzyme appears to be nucleolar bound; 30% is in the nucleoplasm. Studies of the purified enzyme reveal that the enzyme is an endonuclease of estimated molecular weight 16,000. It produces oligonucleotides bearing 5'-phosphate end groups. The enzyme degrades poly(C) and poly(U), as well as rRNA and heterogeneous nuclear RNA, Poly(A), double-stranded RNA, and DNA are not cleaved. The enzyme is heat-labile and is inhibited by 10mM Mg2+ and 50 mM NaCl. The enzyme is probably distinct from previously described nuclear endonucleases.
mesh_terms: D002458:Cell Fractionation; D002466:Cell Nucleolus / Q000201:enzymology; D002467:Cell Nucleus / Q000201:enzymology; D004720:Endonucleases / Q000302:isolation & purification / Q000378:metabolism; D006367:HeLa Cells / Q000201:enzymology*; D007700:Kinetics; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011066:Poly C; D012260:Ribonucleases / Q000302:isolation & purification / Q000378:metabolism; D013045:Species Specificity
chemical_list: D011066:Poly C; D004720:Endonucleases; D012260:Ribonucleases; D010727:Phosphoric Diester Hydrolases