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Proton translocation by cytochrome c oxidase reconstituted into proteoliposomes

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Show simple item record Shaughnessy, Stephen G. en_US 2009-07-09T18:42:25Z 2009-07-09T18:42:25Z 1984-07-09T18:42:25Z
dc.description.abstract Cytochrome c oxidase .inserted into proteoliposomes translocates protons with a stoichiometry of approx-, imately 0.4-0.6 H+/e- in the presence of valinomycin plus pottasium. The existance .ofsuchproton translocation is .supportedby experiments with lauryl maltoside which abolished the pulses but~~d not inhibit cyt. c binding .or oxidase turnover. Pulses with K3FeCN6 did not induce acidification further supporting vectorial proton transport by cyt ..aa3 . Upon lowering the ionic strength and pulsing with ferrocytochrome c, H+/eratios increased. This increase is attributed to scaler proton release consequent upon cyt.c-phospholipid binding. Oxygen pulses at low ionic strength however did not exhibit this large scaler increase in H+/e- ratios.A-small increase was observed upon .02 pul'sing at·low ionic strengt.h. This increase was KeN and, ,pcep sensitive and thus possibly due to a redox linked scaler deprotonation. Increases in the H+/e- ratio also occurred ifp~lses ,were performed in the presence of nonactin rather.than valinomycin. The fluorescent pH indicator pyranine was internally trapped inaa3 conta~ning "proteoliposomes. Internal alkalinization, as mon,itored by pyranine fluorescence leads to a of approx.imately 0.35 units, which is proportional to electron flux. This internal alkalinization was also DCCD sensitive, being inhibited by approximately 50%. This 50% inhibition of internal alkalinization supports the existance of vectorial proton transport. en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Protons. en_US
dc.subject Cytochrome c. en_US
dc.subject Cytochrome oxidase. en_US
dc.subject Liposomes. en_US
dc.subject Protease inhibitors. en_US
dc.title Proton translocation by cytochrome c oxidase reconstituted into proteoliposomes en_US
dc.type Electronic Thesis or Dissertation en_US M.Sc. Biological Sciences en_US Masters en_US
dc.contributor.department Department of Biological Sciences en_US Faculty of Mathematics and Science en_US

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