Isolation and characterization of a ribonuclease from human leukemic blood cells specific for ribonucleic acid of ribonucleic acid deoxyribonucleic acid hybrid molecules

M. G. Sarngadharan, J. P. Leis, R. C. Gallo

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

A ribonuclease that specifically hydrolyzes RNA in RNA DNA hybrids has been purified more than 100 fold from human acute leukemic white blood cells. The mol wt of this enzyme has been estimated as 80,000 by glycerol gradient centrifugation. It requires Mg2+ for activity and is inhibited by N ethylmaleimide. The optimum activity is observed at pH 8 (37°). It is a heat labile protein, t(1/2) at 50° being 2 min. Among the substrates examined, (A)(n) x (dT)(m), (I)(n) x (dC)(m), and phi chi 174 DNA x RNA were hydrolyzed efficiently. (U)(n) x (dA)(m) showed a slight substrate activity, while (C)(n) x (dG)(m) and (G)(n) x (dC)(m) were not significantly hydrolyzed. The enzyme is an endonuclease and does not require RNA ends in the substrate molecule. It is capable of converting more than 95% of the RNA portions in hybrid substrates into acid soluble products which are mono and oligonucleotides terminated in 3' OH and 5' phosphate.

Original languageEnglish (US)
Pages (from-to)365-373
Number of pages9
JournalJournal of Biological Chemistry
Volume250
Issue number2
StatePublished - Dec 1 1975

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Isolation and characterization of a ribonuclease from human leukemic blood cells specific for ribonucleic acid of ribonucleic acid deoxyribonucleic acid hybrid molecules'. Together they form a unique fingerprint.

Cite this