Few studies on purified bacterial reduced diphosphopyridine nucleotide (DPNH) or cytochrome oxidases have been reported, although cytochrome reduction by DPNH’ in crude bacterial extracts has repeatedly been described (l-6). Dolin (7, 8) purified a flavoprotein DPNH oxidase and peroxidase from Streptococcus jaecalis, and Lenhoff and Kaplan (9) and Lenhoff et al. (10) described the characteristi...

OBJECTIVE Cyanotic patients have potentially decreased tissue oxygen tension. Cytochrome oxidase catalyzes the reduction of oxygen and is integral to adenosine triphosphate production. Cytochrome oxidase subunit I, the active site, is encoded by mitochondrial DNA. Using a newborn swine model of chronic hypoxemia, we evaluated ventricular cytochrome oxidase subunit I mRNA and protein expression ...

Cytochrome oxidase is a rate-limiting enzyme in oxidative phosphorylation, the major energy-synthesizing pathway used by the central nervous system, and cytochrome oxidase histochemistry has been extensively utilized to map changes in neural metabolism following experimental manipulations. However, the value of cytochrome oxidase activity in predicting behavior has not been analyzed. We argue t...

Hypoxia/ischaemia is known to trigger neuronal death, but the role of neuronal nitric oxide synthase (nNOS) in this process is controversial. Nitric oxide (NO) inhibits cytochrome oxidase in competition with oxygen. We tested whether NO derived from nNOS synergises with hypoxia to induce neuronal death by inhibiting mitochondrial cytochrome oxidase. Sixteen hours of hypoxia (2% oxygen) plus deo...

Adaptive changes in energy metabolism, as reflected by pyruvate kinase and cytochrome oxidase activities, were examined during in vitro differentiation of the cultivated macrophage. Serum concentrations of tissue culture media, which directly influence endocytic activity, and ambient oxygen tension were both shown to influence pyruvate kinase and cytochrome oxidase activities. Cells maintained ...

Interferon, interferon inducers, and a variety of other immunomodulators are known to depress the hepatic cytochrome P-450 drug-metabolizing system. Two concepts have been proposed to explain this phenomenon. (a) The steady-state of cytochrome P-450 is altered through decreased synthesis and increased degradation of cytochrome P-450 apoprotein. (b) Interferon induces xanthine oxidase; superoxid...

Cytochrome bSh8-d complex, a terminal oxidase in the respiratory chain of Escherichia coli K12 grown under the condition of limited oxygen, was purified to near homogeneity. The purified oxidase complex is composed of equimolar amounts of two polypeptides, with M, = 26,000 and 51,000, determined with gel eIectrophoresis in the presence of sodium dodecyl sulfate. It contains 12.3 nmol of protohe...

A single catalytic site model is proposed to account for the multiphasic kinetics of oxidation of ferrocytochrome c by cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1). This model involves nonproductive binding of substrate to sites near the catalytic site on cytochrome c oxidase for cytochrome c, decreasing the binding constant for cytochrome c at the catalytic site. ...

Cytochrome bSh8-d complex, a terminal oxidase in the respiratory chain of Escherichia coli K12 grown under the condition of limited oxygen, was purified to near homogeneity. The purified oxidase complex is composed of equimolar amounts of two polypeptides, with M, = 26,000 and 51,000, determined with gel eIectrophoresis in the presence of sodium dodecyl sulfate. It contains 12.3 nmol of protohe...

The method used by Potter, Albaum, and others (1, 2) for studying the effects of various inhibitors on cytochrome oxidase has been adapted successfully to the assay of the cytochrome oxidase content of rat tissues. The rate of enzymatic oxidation of reduced cytochrome c is measured. A microadaptation enables the measurement of the cytochrome oxidase content of as little as 4 y (wet weight) of a...