• No se han encontrado resultados

CAPITULO I: El contexto en China y la oportunidad de negocio

CAPITULO 2: La Estrategia a implementar

584. Zweier, J. L. (1988) J. Biol. Chem. 263, 1353 – 1357

585. Karoui, H., Hogg, N., Fréjaville, C., Tordo, P., and Kalyanaraman, B. (1996) J. Biol. Chem. 271, 6000 – 6009

586. Giulivi, C., Poderoso, J. J., and Boveris, A. (1998) J. Biol. Chem. 273, 11038 – 11043 587. Jousserandot, A., Boucher, J.-L., Henry, Y.,

Niklaus, B., Clement, B., and Mansuy, D. (1998) Biochemistry 37, 17179 – 17191 588. Berlett, B. S., and Stadtman, E. R. (1997) J. Biol.

Chem. 272, 20313 – 20316

588a. Rauk, A., and Armstrong, D. A. (2000) J. Am.

Chem. Soc. 122, 4185 – 4192

588b. Messner, K. R., and Imlay, J. A. (1999) J. Biol.

Chem. 274, 10119 – 10128

588c. Srinivasan, C., Liba, A., Imlay, J. A., Valentine, J. S., and Gralla, E. B. (2000) J. Biol. Chem. 275, 29187 – 29192

589. Beckman, K. B., and Ames, B. N. (1997) J. Biol.

Chem. 272, 19633 – 19636

590. Chow, C. K., ed. (1988) Cellular Antioxidant

Defense Mechanisms, CRC Press, Boca Raton,

Florida (3 volumes)

591. Halliwell, B., and Gutteridge, J. M. C. (1986)

Trends Biochem. Sci. 11, 372 – 375

592. Dalton, D. A., Russell, S. A., Hanus, F. J., Pascae, G. A., and Evans, H. J. (1986) Proc.

Natl. Acad. Sci. U.S.A. 83, 3811 – 3815

593. Berger, T. M., Polidori, M. C., Dabbagh, A., Evans, P. J., Halliwell, B., Morrow, J. D., Roberts, L. J., II, and Frei, B. (1997) J. Biol.

Chem. 272, 15656 – 15660

593a. Kirsch, M., and de Groot, H. (2000) J. Biol.

Chem. 275, 16702 – 16708

594. Conklin, P. L., Williams, E. H., and Last, R. L. (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 9970 – 9974

594a. Kirsch, M., and de Groot, H. (2001) FASEB J. 15, 1569 – 1574

595. Christen, S., Woodall, A. A., Shigenaga, M. K., Southwell-Keely, P. T., Duncan, M. W., and Ames, B. N. (1997) Proc. Natl. Acad. Sci. U.S.A. 94, 3217 – 3222

596. Stocker, R., Yamamoto, Y., McDonagh, A. F., Glazer, A. N., and Ames, B. N. (1987) Science 235, 1043 – 1046

597. Peden, D. B., Hohman, R., Brown, M. E., Mason, R. T., Berkebile, C., Fales, H. M., and Kaliner, M. A. (1990) Proc. Natl. Acad. Sci.

U.S.A. 87, 7638 – 7642

598. Reiter, R. J. (1995) FASEB J. 9, 526 – 533 598a. Martín, M., Macías, M., Escames, G., León, J.,

and Acuña-Castroviejo, D. (2000) FASEB J. 14, 1677 – 1679

599. Levine, R. L., Mosoni, L., Berlett, B. S., and Stadtman, E. R. (1996) Proc. Natl. Acad. Sci.

U.S.A. 93, 15036 – 15040

600. Schultz, J. R., Ellerby, L. M., Gralla, E. B., Valentine, J. S., and Clarke, C. F. (1996)

Biochemistry 35, 6595 – 6603

600a. Beyer, R. E., Segura-Aguilar, J., Di Bernardo, S., Cavazzini, M., Fato, R., Fiorentini, D., Galli, M. C., Setti, M., Landi, L., and Lenaz, G. (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 2528 – 2532

600b. Lass, A., and Sohal, R. S. (2000) FASEB J. 14, 87 – 94

600c. Suh, J. H., Shigeno, E. T., Morrow, J. D., Cox, B., Rocha, A. E., Frei, B., and Hagen, T. M. (2001) FASEB J. 15, 700 – 706

601. Wink, D. A., Hanbauer, I., Krishna, M. C., DeGraff, W., Gamson, J., and Mitchell, J. B. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 9813 – 9817

601a. Benaroudj, N., Lee, D. H., and Goldberg, A. L. (2001) J. Biol. Chem. 276, 24261 – 24267 601b. Sun, Q.-A., Kirnarsky, L., Sherman, S., and

Gladyshev, V. N. (2001) Proc. Natl. Acad. Sci.

U.S.A. 98, 3673 – 3678

601c. Kanzok, S. M., Fechner, A., Bauer, H., Ulschmid, J. K., Müller, H.-M., Botella- Munoz, J., Schneuwly, S., Schirmer, R. H., and Becker, K. (2001) Science 291, 643 – 646 601d. Lee, S.-R., Bar-Noy, S., Kwon, J., Levine, R. L.,

Stadtman, T. C., and Rhee, S. G. (2000) Proc.

Natl. Acad. Sci. U.S.A. 97, 2521 – 2526

601e. Lowther, W. T., Brot, N., Weissbach, H., and Matthews, B. W. (2000) Biochemistry 39, 13307 – 13312

601f. St. John, G., Brot, N., Ruan, J., Erdjument- Bromage, H., Tempst, P., Weissbach, H., and Nathan, C. (2001) Proc. Natl. Acad. Sci. U.S.A. 98, 9901 – 9906

601g. Boschi-Muller, S., Azza, S., Sanglier- Cianferani, S., Talfournier, F., Van Dorsselear, A., and Branlant, G. (2000) J. Biol. Chem. 275, 35908 – 35913

601h. Pollock, V. V., and Barber, M. J. (2001)

Biochemistry 40, 1430 – 1440

601i. Bieger, B., and Essen, L.-O. (2001) J. Mol. Biol. 307, 1 – 8

601j. Seo, M. S., Kang, S. W., Kim, K., Baines, I. C., Lee, T. H., and Rhee, S. G. (2000) J. Biol. Chem. 275, 20346 – 20354

602. Deng, H.-X., Hentati, A., Tainer, J. A., Iqbal, Z., Cayabyab, A., Hung, W.-Y., Getzoff, E. D., Hu, P., Herzfeldt, B., Roos, R. P., Warner, C., Deng, G., Soriano, E., Smyth, C., Parge, H. E., Ahmed, A., Roses, A. D., Hallewell, R. A., Pericak-Vance, M. A., and Siddique, T. (1993)

Science 261, 1047 – 1051

602a. Yim, M. B., Kang, J.-H., Yim, H.-S., Kwak, H.- S., Chock, P. B., and Stadtman, E. R. (1996)

Proc. Natl. Acad. Sci. U.S.A. 93, 5709 – 5714

603. Goto, J. J., Gralla, E. B., Valentine, J. S., and Cabelli, D. E. (1998) J. Biol. Chem. 273, 30104 – 30109

603a. Estévez, A. G., Crow, J. P., Sampson, J. B., Reiter, C., Zhuang, Y., Richardson, G. J., Tarpey, M. M., Barbeito, L., and Beckman, J. S. (1999) Science 286, 2498 – 2500

603b. Goto, J. J., Zhu, H., Sanchez, R. J., Nersissian, A., Gralla, E. B., Valentine, J. S., and Cabelli, D. E. (2000) J. Biol. Chem. 275, 1007 – 1014 604. Gardner, P. R., Raineri, I., Epstein, L. B., and

White, C. W. (1995) J. Biol. Chem. 270, 13399 – 13405

605. Gaudu, P., and Weiss, B. (1996) Proc. Roy. Soc.

(London) 93, 10094 – 10098

606. Hidalgo, E., Bollinger, J. M., JR, Bradley, T. M., Walsh, C. T., and Demple, B. (1995) J. Biol.

Chem. 270, 20908 – 20914

607. Demple, B. (1998) Science 279, 1655 – 1656 608. Godon, C., Lagniel, G., Lee, J., Buhler, J.-M.,

Kieffer, S., Perrot, M., Boucherie, H., Toledano, M. B., and Labarre, J. (1998) J. Biol.

Chem. 273, 22480 – 22489

609. Zheng, M., Åslund, F., and Storz, G. (1998)

Science 279, 1718 – 1721

610. Ellis, H. R., and Poole, L. B. (1997) Biochemis-

try 36, 13349 – 13356

610a. Fuangthong, M., and Helmann, J. D. (2002)

Proc. Natl. Acad. Sci. U.S.A. 99, 6690 – 6695

611. Duranteau, J., Chandel, N. S., Kulisz, A., Shao, Z., and Schumacker, P. T. (1998) J. Biol.

Chem. 273, 11619 – 11624

612. Wenger, R. H. (2002) FASEB J. 16, 1151 – 1162 613. DeLong, E. F. (2002) Nature (London) 419, 676 –

677

614. Sinninghe Damsté, J. S., Strous, M., Rijpstra, W. I. C., Hopmans, E. C., Geenevasen, J. A. J., van Duin, A. C. T., van Niftrik, L. A., and Jetten, M. S. M. (2002) Nature (London) 419, 708 – 712

Study Questions Concentrations (mmol/1 of cells) Abbreviation Metabolite Before addition of antimycin After addition of antimycin Glucose 6-phosphate G6P 460 124 Fructose 6-phosphate F6P 150 30 Fructose 1,6-bisphosphate FBP 8 33 Triose phosphates TP 18 59 3-Phosphoglycerate 3PGA 45 106 2-Phosphoglycerate 2PGA 26 19 Phosphoenolpyruvate PEP 46 34 Pyruvate Pyr 126 315 Lactate Lac 1125 8750 ATP 2500 1720 ADP 280 855 AMP 36 206 G6P F6P FDP TP etc.

2. The following problem can be solved using stan- dard reduction potentials (Table 6-8). Use E°’ (pH 7) values for NAD+, enzyme-bound FAD, and

fumarate of –0.32, 0.0, and –0.03 volts, respectively. Values of numerical constants are given in Table 6-1. a) Derive an equation relating the equilibrium

constant for a reaction, Keq, to differences in E0'. 1. Reticulocytes (immature red blood cells) contain

mitochondria that are capable of both aerobic and anaerobic oxidation of glucose. In an experiment using these cells, incubated in oxygenated Krebs – Ringer solution with 10 mM glucose, the addition of antimycin A produced the following changes in metabolite concentration after 15 min (From Ghosh, A. K. and Sloviter, H. A. (1973) J. Biol.

Chem. 248, 3035 – 3040). Interpret the observed

changes in ATP, ADP, and AMP concentrations (see tabulation). Express the concentration of each component after addition of antimycin as a per- centage of that before addition. Then plot the resulting figures for each compound in the sequence found in glycolysis, i.e., label the X axis as follows:

b) Calculate the numerical values of Keq for the reactions

Succinate + NAD+→ Fumarate + NADH + H+

Succinate + FAD → Fumarate + FADH2 at pH 7 and 25°C. The values should be calcu- lated for succinate and the oxidant in the numerator.

3. Compare the catalytic cycles of the following enzymes:

Peroxidase

Cytochrome c oxidase Cytochrome P450

4. What chemical properties are especially important for the following compounds in the electron trans- port complexes of mitochondria?

FAD or FMN

Ubiquinone (coenzyme Q) Cytochrome c

5. Describe the operation of the F1F0ATP synthase of mitochondrial membranes.

6. In studies of mitochondrial function the following stoichiometric ratios have been measured.

a) The P/ O ratio: number of molecules of ATP formed for each atom of oxygen

(as O2) taken up by isolated mitochondria under specified conditions.

b) The ratio of H+ ions translocated across a

mitochondrial inner membrane to the molecules of ATP formed.

c) The ratio of H+ ions pumped out of a

mitochondrion to the number of molecules of ATP formed.

Discuss the experimental difficulties in such measurements. How do uncertainties affect conclusions about the mechanism of ATP synthase? Are the ratios in (b) and (c) above necessarily equal? Explain.

7. Compare P/ O ratios observed for mitochondrial respiration with the following substrates and conditions:

Study Questions a) Oxidation of NADH by O2.

b) Oxidation of succinate by O2. c) Dehydrogenation of ascorbate by O2.

How would the ratio of ATP formed to the num- ber of electrons passing from NADH through the respiratory chain differ for these three oxidants: O2, fumarate, nitrite?

8. What is the mitochondrial glycerol phosphate shuttle? Is it utilized by plant cells? Explain. 9. What chemical reactions are included in these two

important components of the nitrogen cycle (see also Fig. 24-1)?

Nitrification Denitrification

10. What is the difference between a dioxygenase and a monooxygenase? What is meant by a cosubstrate for a monooxygenase?

11. The enzyme p-hydroxybenzoate hydroxylase utilizes a cosubstrate together with O2 to form 3,4-dihydroxybenzoate. Indicate the mechanisms by which the bound FAD cofactor participates in the reaction.

12. What pterin-dependent hydroxylation reactions are important to the human body? Point out similarities and differences between flavin and pterin hydroxylase mechanisms.

13. Describe the basic properties of nitric oxide syn- thases (NOSs) and their varied functions in the body. What are the three different types of NOS? In what ways do they differ?

14. List several compounds that cause oxidative stress in cells and describe some chemical and physio- logical characteristics of each.

15. Propylene glycol is metabolized by several aerobic bacteria to acetoacetate, which can be catabolized as an energy source (see references 509a and 509b). The first step is conversion to an epoxide which reacts further in coenzyme M-dependent and CO2- dependent reactions to form acetoacetate. Can you propose chemical mechanisms?

16. A group of slow-growing denitrifying bacteria obtain energy by oxidizing ammonium ions anaerobically with nitrite ions.613,614

NO2 + NH

4+ → N2 + 2 H2O

Intermediate metabolites are hydroxylamine (H2NOH) and hydrazine (N2H4). The reaction takes place within internal vesicles known as anammoxosomes. Unusual cyclobutane- and cyclohexane-based lipids in their membranes are thought to partially prevent the escape of the toxic intermediates from the anammoxosomes.614

Four protons may move from the cytoplasm into the vesicles for each ammonium ion oxidized. Can you write a reaction sequence? What is the Gibbs energy change for the reaction? How is ATP generated? See p. 1052.

Documento similar