Open AccessMultiple Forms of Nuclear Ribonuclease H from Tetrahymena pyriformis
Author(s) -
TASHIRO Fumio,
MITA Takashi,
HIGASHINAKAGAWA Torn
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10396.x
Subject(s) - ribonuclease , tetrahymena pyriformis , rna , enzyme , dna , tetrahymena , moiety , biochemistry , chemistry , divalent , oligonucleotide , stereochemistry , biology , organic chemistry , gene
Three types of ribonuclease H were detected in the isolated macronuclei of Tetrahymena pyriformis GL, partially purified and characterized. They were eluted at around 0.15 M, 0.3 M and 0.4 M of ammonium chloride in phosphocellulose chromatography, and termed H‐1, H‐2 and 11‐3, respectively. The partially purified enzymes have following properties. a) These enzymes specifically hydrolyze the RNA moiety of RNA. DNA hybrid. Neither DNA moiety of'RNA. DNA hybrid nor the RNA molecule dissociated by heat from RNA. DNA hybrid is hydrolyzed by these enzymes. b) The enzymes are most active at pH 8.5‐9.0. c) They require divalent cations such as Mg 2+ Or Mn 2+ for their activities. The optimal concentrations of these cations are different among these enzymes. d) The mode of cleavage by these enzymes is endonucleolytic, producing mostly oligonucleotides and a small amount of mononueleotIdes which possess 3′‐hydroxyl and 5′‐phosphate termini.