On the Activities of Escherichia coli Exonuclease III

• Published in: Analytical biochemistry Vol. 209; no. 2; pp. 238 - 246
• Main Author: Hoheisel, J.D.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.03.1993; Elsevier
• Subjects: Base Sequence; Biological and medical sciences; Biotechnology; Catalysis; DNA - chemistry; Enzyme Activation; Enzyme engineering; Escherichia coli; Escherichia coli - enzymology; Exodeoxyribonucleases - analysis; Exodeoxyribonucleases - chemistry; Exodeoxyribonucleases - genetics; Fundamental and applied biological sciences. Psychology; Gene Deletion; Kinetics; Methods. Procedures. Technologies; Miscellaneous; Nucleic Acid Conformation; Sodium Chloride - pharmacology; Substrate Specificity; Temperature; 3'-End; Temperature; Enzyme; Gel electrophoresis; Escherichia coli; Environmental factor; Protrusion; Exonuclease; Enzymatic activity; DNA; Concentration effect; Enzymatic digestion; Deletion; Bacteria; Kinetics; Enterobacteriaceae; Sodium Chlorides
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1006/abio.1993.1114

Exonuclease III (Exo III) of Escherichia coli is a DNA-modifying enzyme very frequently used in molecular biology. The experiments described here were carried out with the aims of reliably controlling exonuclease activity and of learning more about the enzyme′s specificities. The dependence of Exo III activity on factors such as temperature (including heat inactivation), the concentrations of Exo III and NaCl, and the concentration and shape of 3′ termini was investigated. Double stranded DNA was found to be a competitive inhibitor of the enzyme activity. Some four nucleotide 3′ protrusions were shown to be sensitive to Exo III digestion. The synchronism of deletion was also examined. Implications for the proposed mechanism of activity are discussed.