Proton pump diagram

Figure 9.8 Simple diagram of mitochondrial H -ion movement and axonal K -ion movement to establish membrane potentials across membranes. Note that H movement from the mitochondrial matrix to the outer surface of the inner membrane requires a specific proton pump that requires energy, which is transferred from electron transfer, whereas the K ion movement occurs via an ion channel with energy provided from the concentration difference of K ions on either side of the membrane (approximately 100-fold). The movement of both the protons and K ions generates a membrane potential. The potential across the membrane of the nerve axon provides the basis for nervous activity (see Chapter 14).

Figure 23-45 (A) Some aspects of the structure of bacteriorhodopsin. Ribbon diagram with the retinal Schiff base in ball-and-stick representation. At the top the helices are labeled as in Fig. 23-41. The locations of aspartate, glutamate, and arginine residues that might carry protons during the proton pumping action are indicated. Retinal is shown attached to lysine 216.

Fig. 1. Schematic diagram showing the different mechanisms of action proposed for the antiulcer action of flavonoids. 1. Blockade of add secretion by decreasing histamine production or inhibiting the proton pump. 2. Bactericidal effect on H. pylori. 3. Antioxidative activity by scavenging free radicals and preventing ROM formation. 4. Potentiation of the mucosal protective factors. PAF platelet activating factor ROM reactive oxygen metabolites H2 histamine receptor 2 M muscarinic receptor G gastrin receptor.

Schematic diagram of one model of the physiologic control of hydrogen ion secretion by the gastric parietal cell. ECL cell, enterochromaffin-like cell G(CCK-B), gastrin-cholecystokinin-B receptor H, histamine H2, histamine H2 receptor Mi, M3, muscarinic receptors ST2, somatostatin2 receptor ATPase, K /H ATPase proton pump. Some investigators place histamine receptors—and possibly cholinoceptors—on nearby tissue cells rather than on the parietal cell itself. (Modified and redrawn from Sachs G, Prinz C Gastric enterochromaffin-like cells and the regulation of acid secretion. News Physiol Sci 1996 11 57, and other sources.)...

FIGURE 6.10 Cartoon representations of protein structures for (a) bovine catalase (Protein Data Bank [PDB] entry SCAT) and (b) bacteriorhodopsin (PDB entry 3WJK), a proton pump similar to the human visual pigment and found in bacterial cells. In these two examples of protein molecules, we can see the amino acid chain coiled and folded into different structures. Alpha-helical structures are shown in red and beta sheets in yellow. Diagrams such as this are commonly used to depict the complex hierarchical structure of proteins. 

Figure C3.2.17. Diagram of a liposome-based artificial photosynthetic membrane showing the photocycle that pumps protons into the interior of the liposome and the CFqF j-ATP synthase enzyme. From [55],...

Figure 6. Pathways of protons and electrons during mitochondrial oxidations. The diagrams show the pathways of electrons which enter the electron chain at the level ofcomplexi (a)orcomplex II (b). Complexes I, III, and IV usethefreeenergy of electron transport to pump protons out of the matrix. This diagram also distinguishes formally between protons released by dehydrogenation and those which are pumped out of the matrix, although they all enter or leave the same pool.

Figure 23-32 Simplified diagram of cyclic electron flow in purple bacteria. Two protons from the cytoplasm bind to QB2 in the reaction center to form QH2 (ubiquinol), which diffuses into the ubiquinone pool. From there it is dehydrogenated by the cytochrome kq complex with expulsion of two protons into the periplasm. A third and possibly a fourth proton may be pumped (green arrows) across the membrane, e.g., via the Q cycle (Fig. 18-9). The protons are returned to the cytoplasm through ATP synthase with formation of ATP. Some electrons may flow to the reaction centers from such reduced substrates as S2 and some electrons may be removed to generate NADPH using reverse electron transport.345...

In addition to the oxygen separation membranes, the proton conducting membranes can also be applied to reduce NO emission by combining heterogeneous catalysis and solid state electrochemistry. The solid electrolytes in MRs serve to electrochemically control chemisorptive bonds and enhance catalytic activity. Figure 8.10 shows the schematic diagram of a steam electrolysis cell constructed with a proton conductor for reducing NO. Steam is electrolyzed at the anode. It shows the produced H+ is electrochemically pumped to the cathode and reacts with NO to produce Nj and HjO ... 

Figure 11.1 Schematic diagram of the apparatus for on-line MS interrogation of a chemical reaction. Pump no. I samples the reaction solution pump no. 2 provides ambient-temperature methanol to quench the reaction, and to carry out primary dilution pump no. 3 is used to meter solution to a flow splitter and pump no. 4 adds dilute HO to enable solute protonation [10], Reprinted with permission from Dell Orco, R, Brum, J., Matsuoka, R., Badlani, M., Muske, K. (1999) Monitoring Process-scale Reactions Using API Mass Spectrometry. Anal. Chem. 71 5165-5170. Copyright (1999) American Chemical Society...

Fig. 10.9 Schematic representation of molecular machineries that confer acetic acid resistance in Acetobacter and Gluconacetobacter. (Schematic diagram quoted from Nakano and Fukaya 2008) THBH and phosphatidylcholine on the membrane and polysaccharide on the surface of the cells are suggested to be involved in acetic acid resistance. Acetic acid, which penetrates into the cytoplasm, is assumed to be metabolized through the TCA cycle by the actions of enzymes typical for AAB. Furthermore, intracellular acetic acid is possibly pumped out by a putative ABC transporter and proton motive force-dependent efflux pump using energy produced by ethanol oxidation or acetic acid overoxidation. Intracellular cytosolic enzymes are intrinsically resistant to low pH and are protected against denaturation by stress proteins such as molecular chaperones. ADH membrane-bound alcohol dehydrogenase, ALDH membrane-bound aldehyde dehydrogenase, CS citrate synthase, ACN aconitase, PC phosphatidylcholine...

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