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...

Cultures of mutant cni-1, a chromosomal mutant of Neurospora crassa, undergo a marked change in respiratory properties as the age of the culture increases. Early log phase cultures have a high level of respiration that is insensitive to inhibition by cyanide or antimycin A. Late log and stationary phase cultures have reduced rates of respiration. A high percentage of this respiration is inhibit...

Numerous attempts have been made to separate the insoluble cytochromes of mammalian heart muscle. Von Euler and Hellstriim in 1939 (1) used sodium cholate and ammonium sulfate and obtained a preparation containing only cytochrome b. Straub (2) obtained a fraction with sodium cholate and ammonium sulfate in which he demonstrated cytochrome oxidase (called cytochrome a3 by him after Keilin and Ha...

The ionic-strength-dependences of the rate constants (log k plotted versus square root of 1) for oxidation of native and pyridoxal 5'-phosphate-modified cytochromes c by three different preparations of cytochrome c oxidase have complex non-linear character, which may be explained on the basis of present knowledge of the structure of the oxidase and the monomer-dimer equilibrium of the enzyme. T...

Cytochrome c oxidase from bovine heart binds Ca(2+) reversibly at a specific Cation Binding Site located near the outer face of the mitochondrial membrane. Ca(2+) shifts the absorption spectrum of heme a, which allowed previously to determine the kinetics and equilibrium characteristics of the binding. However, no effect of Ca(2+) on the functional characteristics of cytochrome oxidase was reve...

Cytochrome oxidase vesicles with high oxidase activity and respiratory control ratio (greater than 3.5) were characterized by the freeze-etch technique for electron microscopy. By the use of this technique, cytochrome oxidase is shown to be an inner membrane particle. By locating cross-fractured vesicles in the same preparation, cytochrome oxidase particles are shown to extend across the phosph...

chloroacetaldehyde (caa) is a chlorination by-product in finished drinking water and a toxic metabolite of a wide variety of industrial chemicals (e.g. vinyl chloride) and chemotherapeutic agents (e.g. cyclophosphamide and ifosfamide). in this research, the cytotoxic mechanisms of caa in freshly isolated rat hepatocytes were investigated.caa cytotoxicity was associated with reactive oxygen spec...

bemisia tabaci (gennadius) (hemiptera: aleyrodidae), is one of the most important pest of vegetable and fruit crops. this polyphagous pest has a range of natural enemies including the parasitoid eretmocerus mundus (merect) (hymenoptera: aphelinidae). to determine the molecular profile and taxonomic status of iranian isolates of e. mundus, parasitized b. tabaci samples were collected from cotton...

OBJECTIVE Despite studies implicating superoxide anion-producing oxidases in atherosclerosis, their characteristics, expression, and regulation in cells of lesions are poorly understood. We examined the following: (1) whether cytochrome b558-dependent NAD(P)H oxidase-phox peptides are expressed by intimal smooth muscle cells (iSMCs) and macrophages of human aortic atherosclerotic lesions and th...

Methyl sterol oxidase of microsomal synthesis of cholesterol from lanosterol is a mixed-function oxidase that is dependent upon reduced pyridine nucleotide. The methyl sterol oxidase, as well as NADH-cytochrome c reductase, in intact rat liver microsomes are inhibited by anti-cytochrome b5 immunoglobulin, but NADPH-cytochrome c reductase is not affected. There is a decreased time lag prior to o...