1. PENTOSE PHOSPHATE CYCLE
79
operative then? The answer to this question hinges on the composition of
the primordial atmosphere of the earth. The general consensus is that
the early atmosphere was a highly reducing one. From this premise
Horecker (510) proposed that the oxidative portion of the pentose cycle
could only come into prominence when the atmosphere turned "oxidizing." From this point of view, at least, the enzymes such as the dehydrogenases evolved rather recently whereas such enzymes as transketolase
and transaldolase may be considered as more primitive. The existence of
these last two enzymes along with enzymes of the EMP pathway in the
primitive organism can thus permit it to carry out metabolism whether
it be photosynthesis or chemosynthesis.
References
1. Ε Bueding and E. Farber, in "Comparative Biochemistry" (M. Florkin and
H. S. Mason, eds.), Vol. I, p. 411. Academic Press, New York, 1960.
2. S. Weinhouse, /. Am. Chem. Soc. 83, 2597 (1961).
3. B. L. Horecker and A. H. Mehler, Ann. Rev. Biochem. 24, 207 (1955).
4. E. Racker, Advances in Enzymol. 15, 141 (1954).
5. B. Axelrod and H. Beevers, Ann. Rev. Phnt Physiol. 7, 267 (1956).
6. M. Gibbs, Ann. Rev. Phnt Physiol. 10, 329 (1959).
7. L. O. Krampitz, in "The Bacteria" (I. C. Gunsalus and R. Y. Stanier, eds.),
Vol. II, p. 209. Academic Press, New York, 1961.
8. S. Abraham, P. Cady, and I. L. Chaikoff, Endocrinology 66, 280 (1960).
9. E. Racker, Arch. Biochem. Biophys. 69, 300 (1957).
10. J. A. Bassham and M. Calvin, "The Path of Carbon in Photosynthesis."
Prentice-Hall, Englewood Cliffs, New Jersey, 1957.
11. R. C. Fuller, R. M. Smillie, E. C. Sisler, and H. L. Kornberg, /. Biol. Chem.
236, 2140 (1961).
12. H. A. Krebs and H. L. Kornberg, Ergeh. Physiol, biol. Chem. u. exptl. Pharmakol. 49, 212 (1957).
13. S. S. Cohen, Cold Spring Harbor Symposia, Quant. Biol. 12, 35 (1947).
14. A. C. Neish, Ann. Rev. Phnt Physiol. 11, 55 (1960).
15. J. J. Burns, in "Metabolic Pathways" (D. M. Greenberg, ed.), Vol. I, p. 341.
Academic Press, New York, 1960.
16. R. Bressler and S. J. Wakil, /. Biol. Chem. 236, 1643 (1961).
17. R. G. Langdon, /. Am. Chem. Soc. 77, 5190 (1955).
18. P. McLean, Biochim. et Biophys. Acta 57, 620 (1962).
19. N. O. Kaplan, M. N. Swartz, M. E. Freeh, and Μ. M. Ciotti, Proc. Natl Acad.
Sei. U. S. 42, 481 (1956).
20. I. C. Gunsalus and C. W. Shuster, in "The Bacteria" (I. C. Gunsalus and
R. Y. Stanier, eds.), Vol. II, p. 1. Academic Press, New York, 1961.
21. O. Warburg and W. Christian, Biochem. Z. 238, 131 (1931).
22. R. O. Loebel, Biochem. Z. 161, 219 (1925).
23. E. S. G. Barron and G. A. Harrop, Jr., /. Biol Chem. 79, 65 (1928).
24. P. A. Levene and F. B. LaForge, J. Biol Chem. 18, 319 (1914).
25. Ε. B. Fred, W. H. Peterson, and J. A. Anderson, /. Biol Chem. 48, 385
(1921).
26. O. Warburg, W. Christian, and A. Griese, Biochem. Z. 282, 157 (1935).
79
operative then? The answer to this question hinges on the composition of
the primordial atmosphere of the earth. The general consensus is that
the early atmosphere was a highly reducing one. From this premise
Horecker (510) proposed that the oxidative portion of the pentose cycle
could only come into prominence when the atmosphere turned "oxidizing." From this point of view, at least, the enzymes such as the dehydrogenases evolved rather recently whereas such enzymes as transketolase
and transaldolase may be considered as more primitive. The existence of
these last two enzymes along with enzymes of the EMP pathway in the
primitive organism can thus permit it to carry out metabolism whether
it be photosynthesis or chemosynthesis.
References
1. Ε Bueding and E. Farber, in "Comparative Biochemistry" (M. Florkin and
H. S. Mason, eds.), Vol. I, p. 411. Academic Press, New York, 1960.
2. S. Weinhouse, /. Am. Chem. Soc. 83, 2597 (1961).
3. B. L. Horecker and A. H. Mehler, Ann. Rev. Biochem. 24, 207 (1955).
4. E. Racker, Advances in Enzymol. 15, 141 (1954).
5. B. Axelrod and H. Beevers, Ann. Rev. Phnt Physiol. 7, 267 (1956).
6. M. Gibbs, Ann. Rev. Phnt Physiol. 10, 329 (1959).
7. L. O. Krampitz, in "The Bacteria" (I. C. Gunsalus and R. Y. Stanier, eds.),
Vol. II, p. 209. Academic Press, New York, 1961.
8. S. Abraham, P. Cady, and I. L. Chaikoff, Endocrinology 66, 280 (1960).
9. E. Racker, Arch. Biochem. Biophys. 69, 300 (1957).
10. J. A. Bassham and M. Calvin, "The Path of Carbon in Photosynthesis."
Prentice-Hall, Englewood Cliffs, New Jersey, 1957.
11. R. C. Fuller, R. M. Smillie, E. C. Sisler, and H. L. Kornberg, /. Biol. Chem.
236, 2140 (1961).
12. H. A. Krebs and H. L. Kornberg, Ergeh. Physiol, biol. Chem. u. exptl. Pharmakol. 49, 212 (1957).
13. S. S. Cohen, Cold Spring Harbor Symposia, Quant. Biol. 12, 35 (1947).
14. A. C. Neish, Ann. Rev. Phnt Physiol. 11, 55 (1960).
15. J. J. Burns, in "Metabolic Pathways" (D. M. Greenberg, ed.), Vol. I, p. 341.
Academic Press, New York, 1960.
16. R. Bressler and S. J. Wakil, /. Biol. Chem. 236, 1643 (1961).
17. R. G. Langdon, /. Am. Chem. Soc. 77, 5190 (1955).
18. P. McLean, Biochim. et Biophys. Acta 57, 620 (1962).
19. N. O. Kaplan, M. N. Swartz, M. E. Freeh, and Μ. M. Ciotti, Proc. Natl Acad.
Sei. U. S. 42, 481 (1956).
20. I. C. Gunsalus and C. W. Shuster, in "The Bacteria" (I. C. Gunsalus and
R. Y. Stanier, eds.), Vol. II, p. 1. Academic Press, New York, 1961.
21. O. Warburg and W. Christian, Biochem. Z. 238, 131 (1931).
22. R. O. Loebel, Biochem. Z. 161, 219 (1925).
23. E. S. G. Barron and G. A. Harrop, Jr., /. Biol Chem. 79, 65 (1928).
24. P. A. Levene and F. B. LaForge, J. Biol Chem. 18, 319 (1914).
25. Ε. B. Fred, W. H. Peterson, and J. A. Anderson, /. Biol Chem. 48, 385
(1921).
26. O. Warburg, W. Christian, and A. Griese, Biochem. Z. 282, 157 (1935).