title: Class I and class II ribonuclease H activities in Crithidia fasciculata (Protozoa).
abstract: The protozoan Crithidia fasciculata contains two different ribonuclease H activities. These enzymes display similar physical and biochemical characteristics to their homologues in higher eukaryotes, for instance calf thymus class I and class II ribonuclease H. Class I ribonuclease H of lower and higher eukaryotes can be activated by Mg2(+)- and Mn2(+)-ions. However, the presence of Mn2(+)-ions is inhibitory for the Mg2(+)-dependent class II ribonuclease H activity of Crithidia fasciculata and calf thymus. The protozoan class I-homologue enzyme appears to be serologically related to the class I ribonuclease H of calf thymus.
authors.affiliation: Biologisches Institut, Universität Tübingen, Federal Republic of Germany.
authors.forename: H
authors.initials: H
authors.lastname: Vonwirth
authors.forename: J
authors.initials: J
authors.lastname: Köck
authors.forename: W
authors.initials: W
authors.lastname: Büsen
mesh_terms: D000818:Animals; D002417:Cattle; D002848:Chromatography, DEAE-Cellulose; D003421:Crithidia / Q000201:enzymology*; D004591:Electrophoresis, Polyacrylamide Gel; D004722:Endoribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D015151:Immunoblotting; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D008970:Molecular Weight; D016914:Ribonuclease H; D013950:Thymus Gland / Q000201:enzymology
chemical_list: D007527:Isoenzymes; D008345:Manganese; D004722:Endoribonucleases; D016914:Ribonuclease H; D008274:Magnesium