Distribution of the tricarboxylic acid cycle enzymes in extracts of escherichia coli

✍ Scribed by Wheat, Robert W. ;Rust, James ;Ajl, Samuel J.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1956
• Tongue: English
• Weight: 956 KB
• Volume: 47
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030470303

✦ Synopsis

It is now certain that the major pathway of terminal respiration in aerobically grown Escherichin coli proceeds c i a the citric acid cycle (Swim and Krampitz, '54; Wheat and Ajl, '54 ; Ajl and Wong, '55). All of the individual oxidative steps, however, have not yet been well characterized. I n order to elucidate the mechanism of the component enzymatic reac- tions of the tricarboxylic acid cycle in this bacterium the separation and purification of the individual enzymes was clearly indicated. An attempt in this direction has been made and the results obtained are described in this report.

The enzymes of the Krebs cycle have been partially separated, their cofactor requirements studied and their relative abundance in cell-free extracts estimated. This work was made possible by the findings of Swim and Krampitz ('52) and Wheat and Ajl ('54) that all substrates participating in the Krebs cycle can be oxidized by cell-free extracts.

Methods

The organism employed in this work was Escherichia coli, strain E26. It was grown for 18 hours at 37°C. with vigorous aeration in an acetate medium (A$' '50) containing 0.2% yeast extract.