EFRAIM RACKER 



have been described which await further study; many more 

 enzymes will be discovered in the future; nearly endless seems 

 the number of enzymes which might be induced by adaptive 

 processes or might be selected in microorganisms fished from the 

 mud of California. It is clear that the availability of enzymes will 

 not be the limiting factor in the future of enzymology. The 

 purification of enzymes is gradually becoming a routine pro- 

 cedure and biochemists are beginning to attach to it the 

 stigma of a necessary evil. The protein chemists are turning to 

 sequence analysis and to a search of the chemical properties of 

 the active centers and their neighborning groups. The kineti- 

 cists, after collecting essential data on the interaction between 

 the substrate and various intracellular and surface enzymes, are 

 beginning to return to more complex multienzyme systems and 

 even approach the kinetics of the intact cell. Their studies may 

 bring new clues to the great physiological mystery of the mode 

 of substrate entry into the cell. Enzymes as analytical tools will 

 undoubtedly infiltrate further into the laboratories at the ex- 

 treme wings of biochemistry: physical chemistry and medical 

 diagnostics. Many more enzymes will be investigated as reac- 

 tants, and cycle after cycle will appear on the surface of the deep 

 waters of metabolism. 



References 



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la. Anfinsen, C. B., Biochim. et Biophys. Acta, 17, 593 (1955). 



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2. Bergmann, M., Harvey Lectures, Ser. 31 , 37 (1936). 



2a. Bier, M., J. Sri Ram, and F. F. Nord, Nature, 176, 789 (1955). 



3. Biicher, T., and K. Garbade, Biochim. et Biophys. Acta, 8, 220 (1952). 



4. Chance. B., in Modern Trends in Physiol, and Biochem., 1952, 25. 



5. Chance, B., in W. D. McElroy and B. Glass, eds.. Mechanism of Enzyme 

 Action, p. 399. Johns Hopkins Press, Baltimore, 1954. 



6. Colvin, J. R., D. B. Smith, and W. H. Cook, Chem. Revs., 54, 687 (1954). 

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