scholarly journals The role of cytochrome c4 in bacterial respiration. Cellular location and selective removal from membranes

1989 ◽  
Vol 262 (1) ◽  
pp. 233-240 ◽  
Author(s):  
D J B Hunter ◽  
K R Brown ◽  
G W Pettigrew
Keyword(s):  
Oxidase Activity ◽  
Sodium Iodide ◽  
Azotobacter Vinelandii ◽  
Pseudomonas Stutzeri ◽  
Selective Removal ◽  
Bacterial Respiration ◽  
Cellular Location ◽  
Diamine Oxidase Activity ◽  
Membrane Bound

The cellular location of cytochrome c4 in Pseudomonas stutzeri and Azotobacter vinelandii was investigated by the production of spheroplasts. Soluble cytochrome c4 was found to be located in the periplasm in both organisms. The remaining cytochrome c4 was membrane-bound. The orientation of this membrane-bound cytochrome c4 fraction was investigated by proteolysis of the cytochrome on intact spheroplasts. In P. stutzeri, 78% of the membrane-bound cytochrome c4 could be proteolysed, whilst 82% of the spheroplasts remained intact, suggesting that the membrane-bound cytochrome c4 is on the periplasmic face of the membrane in this organism. Cytochrome c4 was not susceptible to proteolysis on A. vinelandii spheroplasts, in spite of being digestible in the purified state. Cytochrome c5 was shown to have a similar cellular distribution to cytochrome c4. Selective removal of cytochrome c4 from membranes of P. stutzeri was accomplished by the use of sodium iodide and propan-2-ol, with the retention of most of the ascorbate-TMPD (NNN‘N’-tetramethylbenzene-1,4-diamine) oxidase activity associated with the membrane. Sodium iodide removed most of the cytochrome c4 from A. vinelandii membranes with retention of 62% of the ascorbate-TMPD oxidase activity. Cytochrome c4 could be returned to the washed membranes, but with no recovery of this enzyme activity. We conclude that cytochrome c4 is not involved in the ascorbate-TMPD oxidase activity associated with the membranes of these two organisms.

scholarly journals Free and membrane-bound forms of bacterial cytochrome c4

1988 ◽  
Vol 252 (2) ◽  
pp. 427-435 ◽  
Author(s):  
G W Pettigrew ◽  
K R Brown
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Azotobacter Vinelandii ◽  
Pseudomonas Stutzeri ◽  
Growth Conditions ◽  
Free Form ◽  
Aerobic Growth ◽  
Cytochromes C ◽  
Membrane Bound ◽  
Solubilized Form ◽  
Attached Form

Cytochrome c4 was isolated from cells of Pseudomonas aeruginosa, Pseudomonas stutzeri and Azotobacter vinelandii. The dihaem nature, Mr of approx. 20,000 and ferrohaem spectra in the region of the alpha- and beta-peaks define this family of cytochromes c. The behaviour of the holocytochromes in SDS was atypical, but removal of the haem groups resulted in a normal migration. In all three organisms most of the cytochrome c4 was tightly bound to the membrane, but some free cytochrome was detected. The membrane-attached cytochrome could be extracted with butanol, and this solubilized form was then indistinguishable in properties from the free form. Denitrifying rather than aerobic growth conditions hardly affected the total cytochrome c4 in the two pseudomonads, but there was slightly more free form and less membrane-attached form in denitrifying growth. The nature of the attachment of cytochrome c4 to the membrane is discussed and a model is proposed for the process of solubilization.

scholarly journals FcγR-stimulated activation of the NADPH oxidase: phosphoinositide-binding protein p40phox regulates NADPH oxidase activity after enzyme assembly on the phagosome

Blood ◽  
2008 ◽  
Vol 112 (9) ◽  
pp. 3867-3877 ◽  
Author(s):  
Wei Tian ◽  
Xing Jun Li ◽  
Natalie D. Stull ◽  
Wenyu Ming ◽  
Chang-Il Suh ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Superoxide Production ◽  
Resting Cells ◽  
Cellular Activation ◽  
Nadph Oxidase Activity ◽  
Phagocyte Nadph Oxidase ◽  
Before And After ◽  
Membrane Bound

AbstractThe phagocyte NADPH oxidase generates superoxide for microbial killing, and includes a membrane-bound flavocytochrome b558 and cytosolic p67phox, p47phox, and p40phox subunits that undergo membrane translocation upon cellular activation. The function of p40phox, which binds p67phox in resting cells, is incompletely understood. Recent studies showed that phagocytosis-induced superoxide production is stimulated by p40phox and its binding to phosphatidylinositol-3-phosphate (PI3P), a phosphoinositide enriched in membranes of internalized phagosomes. To better define the role of p40phox in FcγR-induced oxidase activation, we used immunofluorescence and real-time imaging of FcγR-induced phagocytosis. YFP-tagged p67phox and p40phox translocated to granulocyte phagosomes before phagosome internalization and accumulation of a probe for PI3P. p67phox and p47phox accumulation on nascent and internalized phagosomes did not require p40phox or PI3 kinase activity, although superoxide production before and after phagosome sealing was decreased by mutation of the p40phox PI3P-binding domain or wortmannin. Translocation of p40phox to nascent phagosomes required binding to p67phox but not PI3P, although the loss of PI3P binding reduced p40phox retention after phagosome internalization. We conclude that p40phox functions primarily to regulate FcγR-induced NADPH oxidase activity rather than assembly, and stimulates superoxide production via a PI3P signal that increases after phagosome internalization.

scholarly journals Electron transport in Paracoccus halodenitrificans and the role of Ubiquinone

1984 ◽  
Vol 30 (5) ◽  
pp. 572-577 ◽  
Author(s):  
Lawrence I. Hochstein ◽  
Sonja E. Cronin
Keyword(s):  
Enzyme Activity ◽  
Electron Transport ◽  
Ultraviolet Irradiation ◽  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Succinate Oxidation ◽  
Partial Restoration ◽  
Membrane Bound ◽  
Nadh Oxidase Activity

The membrane-bound NADH oxidase of Paracoccus halodenitrificans was inhibited by dicoumarol, 2-n-heptyl-4-hydroxyquinoline-N-oxide (HQNO), and exposure to ultraviolet light (at 366 nm). When the membranes were extracted with n-pentane, NADH oxidase activity was lost. Partial restoration was achieved by adding the ubiquinone fraction extracted from the membranes. Succinate oxidation was not inhibited by dicoumarol or HQNO, but was affected by ultraviolet irradiation or n-pentane extraction. However, the addition of the ubiquinone fraction to the membranes extracted with n-pentane did not restore enzyme activity. These observations suggested that NADH and succinate were not oxidized through a common ubiquinone pool.

scholarly journals Stability of the cbb3-Type Cytochrome Oxidase Requires Specific CcoQ-CcoP Interactions

2008 ◽  
Vol 190 (16) ◽  
pp. 5576-5586 ◽  
Author(s):  
Annette Peters ◽  
Carmen Kulajta ◽  
Grzegorz Pawlik ◽  
Fevzi Daldal ◽  
Hans-Georg Koch
Keyword(s):  
Oxidase Activity ◽  
Rhodobacter Capsulatus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Growth Conditions ◽  
Native Polyacrylamide Gel Electrophoresis ◽  
Membrane Bound ◽  
Binuclear Center ◽  
The Stability ◽  
Copper Oxidase

ABSTRACT Cytochrome cbb 3-type oxidases are members of the heme copper oxidase superfamily and are composed of four subunits. CcoN contains the heme b-CuB binuclear center where oxygen is reduced, while CcoP and CcoO are membrane-bound c-type cytochromes thought to channel electrons from the donor cytochrome into the binuclear center. Like many other bacterial members of this superfamily, the cytochrome cbb 3-type oxidase contains a fourth, non-cofactor-containing subunit, which is termed CcoQ. In the present study, we analyzed the role of CcoQ on the stability and activity of Rhodobacter capsulatus cbb 3-type oxidase. Our data showed that CcoQ is a single-spanning membrane protein with a Nout-Cin topology. In the absence of CcoQ, cbb 3-type oxidase activity is significantly reduced, irrespective of the growth conditions. Blue native polyacrylamide gel electrophoresis analyses revealed that the lack of CcoQ specifically impaired the stable recruitment of CcoP into the cbb 3-type oxidase complex. This suggested a specific CcoQ-CcoP interaction, which was confirmed by chemical cross-linking. Collectively, our data demonstrated that in R. capsulatus CcoQ was required for optimal cbb 3-type oxidase activity because it stabilized the interaction of CcoP with the CcoNO core complex, leading subsequently to the formation of the active 230-kDa cbb 3-type oxidase complex.

PP165-MON THE INFLUENCE OF MENSTRUAL CYCLE ON SERUM DIAMINE OXIDASE ACTIVITY IN HEALTHY WOMEN

2011 ◽  
Vol 6 (1) ◽  
pp. 176-177
Author(s):  
Y. Hamada ◽  
Y. Shinohara ◽  
M. Yano ◽  
M. Yamamoto ◽  
M. Yoshio ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Oxidase Activity ◽  
Diamine Oxidase ◽  
Healthy Women ◽  
Diamine Oxidase Activity

scholarly journals Genetic and Phenotypic Analyses of therdx Locus of Rhodobacter sphaeroides2.4.1

2000 ◽  
Vol 182 (12) ◽  
pp. 3475-3481 ◽  
Author(s):  
Jung Hyeob Roh ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Redox Protein ◽  
Deletion Mutations ◽  
Metal Transporter ◽  
New Class ◽  
Mutant Strains ◽  
Membrane Bound ◽  
Photosynthesis Gene

ABSTRACT Previously, we reported that rdxB, encoding a likely membrane-bound two [4Fe-4S]-containing center, is involved in the aerobic regulation of photosystem gene expression in Rhodobacter sphaeroides 2.4.1. To further investigate the role ofrdxB as well as other genes of the rdxBHISoperon on photosystem gene expression, we constructed a series of nonpolar, in-frame deletion mutations in each of the rdxgenes. Using both puc and puf operonlacZ fusions to monitor photosystem gene expression, under aerobic conditions, in each of the mutant strains revealed significant increased photosynthesis gene expression. In the case of mutations in either rdxH, rdxI, or rdxS, the aerobic induction of photosystem gene expression is believed to be indirect by virtue of a posttranscriptional effect oncbb 3 cytochrome oxidase structure and integrity. For RdxB, we suggest that this redox protein has a more direct effect on photosystem gene expression by virtue of its interaction with the cbb 3 oxidase. An associated phenotype, involving the enhanced conversion of the carotenoid spheroidene to spheroidenone, is also observed in the RdxB, -H, -I, and -S mutant strains. This phenotype is also suggested to be the result of the role of the rdxBHIS locus incbb 3 oxidase activity and/or structure. RdxI is suggested to be a new class of metal transporter of the CPx-type ATPases.

Predictive role of nontumoral sodium iodide symporter activity and preoperative thyroid characteristics in remission process of thyroid cancer patients

2014 ◽  
Vol 28 (7) ◽  
pp. 623-631 ◽  
Author(s):  
Nilufer Yildirim-Poyraz ◽  
Aylin Yazgan ◽  
Elif Ozdemir ◽  
Aysegul Gozalan ◽  
Mutlay Keskin ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Cancer Patients ◽  
Sodium Iodide ◽  
Sodium Iodide Symporter ◽  
Predictive Role

scholarly journals Advances in understanding the role of cardiac glycosides in control of sodium transport in renal tubules

2014 ◽  
Vol 222 (1) ◽  
pp. R11-R24 ◽  
Author(s):  
Syed Jalal Khundmiri
Keyword(s):  
Heart Failure ◽  
Intracellular Signaling ◽  
Cardiac Contractility ◽  
Myocardial Cell ◽  
Renal Tubules ◽  
Intracellular Signaling Pathway ◽  
Body Sodium ◽  
Membrane Bound ◽  
Total Body

Cardiotonic steroids have been used for the past 200 years in the treatment of congestive heart failure. As specific inhibitors of membrane-bound Na+/K+ATPase, they enhance cardiac contractility through increasing myocardial cell calcium concentration in response to the resulting increase in intracellular Na concentration. The half-minimal concentrations of cardiotonic steroids required to inhibit Na+/K+ATPase range from nanomolar to micromolar concentrations. In contrast, the circulating levels of cardiotonic steroids under physiological conditions are in the low picomolar concentration range in healthy subjects, increasing to high picomolar levels under pathophysiological conditions including chronic kidney disease and heart failure. Little is known about the physiological function of low picomolar concentrations of cardiotonic steroids. Recent studies have indicated that physiological concentrations of cardiotonic steroids acutely stimulate the activity of Na+/K+ATPase and activate an intracellular signaling pathway that regulates a variety of intracellular functions including cell growth and hypertrophy. The effects of circulating cardiotonic steroids on renal salt handling and total body sodium homeostasis are unknown. This review will focus on the role of low picomolar concentrations of cardiotonic steroids in renal Na+/K+ATPase activity, cell signaling, and blood pressure regulation.

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