title: An activity stain for dihydroxy-acid dehydratase.
abstract: An activity stain has been devised for the dihydroxy-acid dehydratase. When applied to polyacrylamide gel electropherograms of crude soluble extracts of Escherichia coli, it detected a single electromorph. The intensity of staining increased with the amount of extract protein applied to the gel. Activity staining demonstrated that (a) anaerobically grown cells contain more extractable dehydratase activity than do aerobically grown cells; (b) exposure of E. coli to 4.2 atm O2 caused virtually complete loss of activity; (c) exposure of cells to paraquat or plumbagin in the presence of dioxygen, but not in its absence, caused a massive loss of activity. These data illustrate the utility of this activity stain and demonstrate that the dehydratase is inactivated by O2- generated within cells.
mesh_terms: D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D006836:Hydro-Lyases / Q000032:analysis* / Q000037:antagonists & inhibitors; D009285:Naphthoquinones / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D013194:Staining and Labeling / Q000379:methods*; D013481:Superoxides / Q000378:metabolism
chemical_list: D009285:Naphthoquinones; D013481:Superoxides; D006836:Hydro-Lyases; C020052:dihydroxyacid dehydratase; D010269:Paraquat; C014758:plumbagin