title: Activation studies by phospholipids on the purified cytochrome c4:o oxidase of Azotobacter vinelandii.
abstract: A modified procedure is described that was used to solubilize and purify the TMPD-dependent cytochrome c4:o oxidase from Azotobacter vinelandii. Two functional components (Fractions I and V) were obtained after DEAE-cellulose chromatography. Fraction V contained both cytochrome c4 (3.6 nmol/mg protein) and cytochrome o (1.6 nmol/mg protein). This cytochrome oxidase complex oxidized TMPD at "moderate" rates. Fraction I, a clear greenish-yellow fraction, contained primarily phosphatidylethanolamine with some phosphatidylglycerol. Fraction I itself could not oxidize TMPD, but when it was preincubated with Fraction V, a 2-4-fold stimulation in TMPD oxidase activity occurred. Other "authentic" micellar phospholipids also readily activated TMPD oxidase activity in Fraction V. The maximum activation effect obtained with Fraction I was in essence duplicated with purified phosphatidylethanolamine.
mesh_terms: D001395:Azotobacter / Q000201:enzymology*; D003573:Cytochrome b Group; D003574:Cytochrome c Group / Q000302:isolation & purification / Q000378:metabolism*; D003580:Cytochromes / Q000302:isolation & purification / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000302:isolation & purification / Q000378:metabolism*; D004789:Enzyme Activation; D029968:Escherichia coli Proteins; D010084:Oxidation-Reduction; D010089:Oxidoreductases, N-Demethylating / Q000302:isolation & purification*; D010743:Phospholipids / Q000378:metabolism; D013057:Spectrum Analysis; D013772:Tetramethylphenylenediamine / Q000378:metabolism
chemical_list: D003573:Cytochrome b Group; D003574:Cytochrome c Group; D003580:Cytochromes; D029968:Escherichia coli Proteins; D010743:Phospholipids; C034186:cytochrome C4; C017168:cytochrome bo, E coli; D010089:Oxidoreductases, N-Demethylating; C022726:tetramethylphenylenediamine oxidase; D003576:Electron Transport Complex IV; D013772:Tetramethylphenylenediamine