Document 0251 DOCN M9620251 TI In vitro activity of minimised hammerhead ribozymes. DT 9602 AU Hendry P; McCall MJ; Santiago FS; Jennings PA; CSIRO, Division of Biomolecular Engineering, North Ryde, NSW,; Australia. SO Nucleic Acids Res. 1995 Oct 11;23(19):3922-7. Unique Identifier : AIDSLINE MED/96038849 AB A number of minimised hammerhead ribozymes (minizymes) which lack stem II have been kinetically characterised. These minizymes display optimal cleavage activity at temperatures around 37 degrees C. The cleavage reactions of the minizymes are first order in hydroxide ion concentration up to around pH 9.3 above which the cleavage rate constants decline rapidly. The reactions show a biphasic dependence on magnesium-ion concentration; one of the interactions has an apparent dissociation constant of around 20 mM while the other appears to be very weak, showing no sign of saturation at 200 mM MgCl2. The minizymes are significantly less active than comparable, full-size ribozymes when cleaving short substrates. However, at a particular site in a transcribed TAT gene from HIV-1, minizymes are more effective than ribozymes. DE Animal Base Sequence Comparative Study Drosophila melanogaster/GENETICS DNA-Binding Proteins/GENETICS Genes, tat Hydrogen-Ion Concentration HIV-1/GENETICS Kinetics Magnesium/PHARMACOLOGY Molecular Sequence Data Nucleic Acid Conformation Rats RNA, Catalytic/CHEMISTRY/*METABOLISM RNA, Messenger/CHEMISTRY/METABOLISM Somatotropin/GENETICS Substrate Specificity Temperature Transcription Factors/GENETICS JOURNAL ARTICLE SOURCE: National Library of Medicine. NOTICE: This material may be protected by Copyright Law (Title 17, U.S.Code).