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RNA ligase in eukaryotic mammalian cells was studied by using mouse brain and livercell extracts as enzyme sources and Oligo A as substrates. RNA ligase activity was deter-mined by measuring the formation of alkaline phosphate-resistant product from 5’-~32P-termi-hated Oligoribonucleotides. Under appropriate conditions, the activity of this enzyme inbrain and liver cells may vary between 16-49 mU/ml. The joining way between donorand acceptor is 5’-P→3’-OH. Further studies wore carried out by using synthetic UpCpUand ~32pNp as substrates and crude enzyme preparations from extracts of cell unclei of brainand liver as enzyme sources. RNA ligase activity was examined by homochromatographyand autoradiography. A clear joining product was demonstrated and then isolated from thereaction mixture by DEAE-Sephadex A25 column chromatography. The eluted fractionswere identified by DEAE-cellulose thin layer chromatography. The joining product washydrolyzed either with KOH or with alkaline phosphatase, the autoradiog
RNA ligase in eukaryotic mammalian cells was studied by using mouse brain and liver cell extracts as enzyme sources and Oligo A as substrates. RNA ligase activity was deter- mined by measuring the formation of alkaline phosphate-resistant product from 5’-32P-termi- hated Oligoribonucleotides. Under appropriate conditions, the activity of this enzyme inbrain and liver cells may vary between 16-49 mU / ml. The joining way between donorand acceptor is 5’-P → 3’-OH. Further studies wore carried out by using synthetic UpCpUand ~ 32pNp as substrates and crude enzyme preparations from extracts of cell unclei of brain and liver as enzyme sources. RNA ligase activity was examined by homochromatography and autoradiography. A clear joining product was demonstrated and then isolated from thereaction mixture by DEAE-Sephadex A25 column chromatography The eluted fractions were identified by DEAE-cellulose thin layer chromatography. The joining product washydrolyzed either with KOH or with alkaline phosphat ase, the autoradiog