Abstract
Summary: Treatment of growing Mycobacterium smegmatis with hydroxyurea decreased the DNA/protein ratio and markedly increased the specific activities of DNA polymerase and ATP-dependent deoxyribonuclease. These changes were similar to those produced by iron limitation of growth. Treating M. smegmatis with nalidixic acid also decreased the DNA/protein ratio but had no effect on the activity of either enzyme. Growth of M. smegmatis under conditions of zinc limitation did not diminish the specific activity of DNA polymerase thus not favouring a role for zinc in the action of this enzyme. The activity of the ATP-dependent deoxyribonuclease was, however, slightly increased. In previous reports the specific activity of DNA polymerase in this organism has been seriously underestimated due to interfering deoxyribonuclease and nucleoside triphosphatase. This was corrected by sufficient dilution of the extract. Revised specific activities of DNA polymerase in carbon-limited, nitrogen-limited and iron-limited cultures are, respectively, 10, 14, 11 and 64 units/mg protein.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
