scholarly journals The microbiol metabolism of C1 compounds. Oxidative phosphorylation in membrane preparations of Pseudomonas AM1

1979 ◽  
Vol 178 (2) ◽  
pp. 353-360 ◽  
Author(s):  
Alexander I. Netrusov ◽  
Christopher Anthony
Keyword(s):  
Oxidative Phosphorylation ◽  
Adenosine Triphosphatase ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Membrane Vesicles ◽  
Antimycin A ◽  
O2 Consumption ◽  
Whole Cells ◽  
Carbonyl Cyanide ◽  
Cytochromes C

A method is described for preparation of membrane vesicles (diameter 80nm) capable of respiration-linked ATP synthesis. Vesicles prepared from succinate-grown bacteria oxidized NADH, succinate and ascorbate plus NNN′N′-tetramethylphenylenediamine; vesicles prepared from methanol-grown bacteria also oxidized methanol and formaldehyde, but they were otherwise identical. The uncoupling agent carbonyl cyanide chlorophenylhydrazone and the adenosine triphosphatase inhibitor dicyclohexylcarbodi-imide both inhibited ATP synthesis, whereas they had no effect on the rate of respiration. Rotenone inhibited ATP synthesis and respiration with NADH as substrate; antimycin A inhibited with succinate as substrate, and cyanide inhibited with all substrates. P/O ratios were usually 0.7–1.3 with NADH, 0.6–1.0 with succinate and 0.2–0.6 with reduced NNN′N′-tetramethylphenylenediamine or methanol as respiratory substrate. When 2,6-dichlorophenol-indophenol was used as an alternative electron acceptor to O2 (NADH as donor) the P/2e ratio was 1.65. Although these P/O ratios are minimum values, because they do not take into account unknown amounts of uncoupled O2 consumption, they are consistent with previous proposals [O'Keeffe & Anthony (1978) Biochem, J.170, 561–567] based on measurements of proton translocation in whole cells. The results also confirm that methanol dehydrogenase and cytochromes c and a/a3 are arranged so that the first step in methanol oxidation is coupled to synthesis of ATP.

scholarly journals Studies of energy-linked reactions. Net synthesis of adenosine triphosphate by isolated adenosine triphosphate synthase preparations: a role for lipoic acid and unsaturated fatty acids

1976 ◽  
Vol 160 (3) ◽  
pp. 809-812 ◽  
Author(s):  
D E Griffiths
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Oxidative Phosphorylation ◽  
Adenosine Triphosphate ◽  
Atp Synthase ◽  
Lipoic Acid ◽  
Adenosine Triphosphatase ◽  
Unsaturated Fatty Acids ◽  
Atp Synthesis ◽  
Substrate Level

ATP synthase preparations [complex V, proton-translocatin ATPase (adenosine triphosphatase) and oligomycin-sensitive ATPase] contain stoicheiometric amounts of lipoic acid residues (up to 6mol of lipoic acid/mol of ATPase complex) and catalyse net ATP synthesis in an uncoupler-and oligomycin-sensitive reaction utilizing dihydrolipoate, oleoyl-CoA and oleic acid, or in a reaction utilizing oleoyl-S-lipoate. The terminal reactions of oxidative phosphorylation are thus analogous to those of substrate-level phosphorylation.

scholarly journals Adenosine triphosphate-evoked catecholamine release in chromatin granules. Osmotic lysis as a consequence of proton translocation

1976 ◽  
Vol 158 (3) ◽  
pp. 583-588 ◽  
Author(s):  
R P Casey ◽  
D Njus ◽  
G K Radda ◽  
P A Sehr
Keyword(s):  
Oxidative Phosphorylation ◽  
Adenosine Triphosphate ◽  
Adenosine Triphosphatase ◽  
Proton Translocation ◽  
Catecholamine Release ◽  
Chromaffin Granules ◽  
Release Process ◽  
Media Release ◽  
Osmotic Lysis ◽  
Permeant Anion

Chromaffin granules suspended in C1-containing media release catecholamine and protein when ATP is added. This phenomenon is inhibited in hyperosmotic media and in the presence of uncouplers of oxidative phosphorylation. Release requires a permeant anion in the medium, but is independent of the cation. The release process appears to be driven by an inwardly directed proton-translocating adenosine triphosphatase. The resulting proton-anion influx causes osmotic lysis of the chromaffin granules.

Carotid body O2 chemoreception and mitochondrial oxidative phosphorylation

1981 ◽  
Vol 51 (2) ◽  
pp. 438-446 ◽  
Author(s):  
E. Mulligan ◽  
S. Lahiri ◽  
B. T. Storey
Keyword(s):  
Oxidative Phosphorylation ◽  
Carotid Body ◽  
High Energy ◽  
Metabolic Inhibitors ◽  
Antimycin A ◽  
Mitochondrial Oxidative Phosphorylation ◽  
High Energy Phosphate ◽  
Afferent Fibers ◽  
Carbonyl Cyanide ◽  
Stimulation Of

The effect on carotid chemoreceptor afferents of oligomycin, an inhibitor of mitochondrial oxidative phosphorylation that does not affect energy conservation, was studied in 20 cats that were anesthetized, paralyzed, and artificially ventilated. Responses of single or a few chemoreceptor afferents to changes in arterial O2 tension (PaO2) at constant arterial CO2 tension were recorded. In addition, responses to nicotine, cyanide, and antimycin A or carbonyl cyanide p-tri-fluoromethoxyphenylhydrazone (FCCP) were tested in normoxia. Oligomycin (50-500 microgram) was administered by close intra-arterial injection, and the same tests were repeated at timed intervals. Initially, oligomycin caused vigorous stimulation of carotid chemoreceptor activity. Subsequently, although the afferent fibers were still active and could be vigorously stimulated by nicotine, they no longer responded to changes in PaO2 or to doses of cyanide, antimycin A, or FCCP. These results separate stimulation of chemoreceptor afferents by hypoxia and metabolic inhibitors and uncouplers from that by nicotine and suggest that intact oxidative phosphorylation, required for maintenance of the intracellular high-energy phosphate levels, forms the basis of O2 chemoreception in the carotid body.

The Leeuwenhoek Lecture, 1981 - The biochemical and genetic approach to the study of bioenergetics with the use of Escherichia coli : progress and prospects

1982 ◽  
Vol 215 (1198) ◽  
pp. 1-18 ◽  
Keyword(s):  
Escherichia Coli ◽  
Cell Membrane ◽  
Oxidative Phosphorylation ◽  
Adenosine Triphosphatase ◽  
Atp Synthesis ◽  
Genetic Approach ◽  
Biochemical Genetics ◽  
Multiprotein Complex ◽  
E Coli ◽  
And Function

How the ‘energy currency’ of the cell, adenosine triphosphate (ATP), is produced consequent upon the oxidation of foodstuffs (oxidative phosphorylation) is, despite prolonged research, still a matter of debate and the molecular mechanism of the process is unknown. It appears that the problem of oxidative phosphorylation can be approached with the aid of the biochemical genetics of the bacterium Escherichia coli . The ease of manipulation of bacteria and definitive results obtained by this approach have been invaluable in solving other major biochemical problems. Mutants affected in oxidative phosphorylation have been isolated and characterized by genetic and biochemical techniques. These ‘ unc ' mutants are affected in the adenosine triphosphatase (ATPase) multiprotein complex which is part of the cell membrane and responsible for the terminal stages of ATP synthesis. Seven distinct genes concerned with oxidative phosphorylation have been characterized in E. coli and shown to be part of an operon. The relationships between the different classes of unc genes and the various components of the ATPase have been established. Information about the assembly of the ATP synthesizing complex in the cell membrane has also been obtained and the stage set for further studies on the assembly, control and function of the ATP synthesizing system.

On the mechanism of ATP synthesis in oxidative phosphorylation: A review

1974 ◽  
Vol 3 (1) ◽  
pp. 1-15 ◽  
Author(s):  
John H. Young ◽  
Ephraim F. Korman ◽  
Jerome McLick
Keyword(s):  
Oxidative Phosphorylation ◽  
Atp Synthesis
Sign in / Sign up

Export Citation Format

Share Document