Specific Mechanisms of Protein Synthesis in the Developing Chick Embryo 133 



A similar observation has been reported by Kutsky who found the supernatant 



fraction of embryo extract to be most active in stimulating the growth of heart 



fibroblasts in vitro (36). 



REFERENCES 



1. For a very stimulating and up to date review the reader is referred to: B. Ephrussi: 

 Enzymes in Cellular Differentiation, in: O. H. Gaebler: Enzymes: Units of Biological 

 Structure and Function, Academic Press, New York City, 29-40 (1956). 



2. For an intriguing hypothesis involving control of organ development by diffusible com- 

 ponents see the following articles: P. Weiss, in A. K. Parpart: The Chemistry and 

 Physiology of Growth, Princeton University Press, 135-186 (1949). 



P. Weiss: Self regulation of organ growth by its own products. Science 115, 487-488 



(1952). 



P. Weiss: Some introductory remarks on the cellular basis of differentiation. /. Embryol. 



Exp. Morph. 1, 181-211 (1953). 



3. The present state of knowledge, with special emphasis on protein biosynthesis, is admirably 

 reviewed in the following: J. D. Ebert: Some aspects of protein biosynthesis in develop- 

 ment, in: D. Rudnick: Aspects of Synthesis and Order in Growth, Princeton University 

 Press, 69-112(1956). 



4. S.Spiegelman: On the nature of the enzyme-forming system, />;; O. H. Gaebler: Enzymes: 

 Units of Biological Structure and Function, Academic Press, New York City, 67-89 

 (1956). 



5. R. S. Alcock: The synthesis of proteins in vivo. Physiol. Rev. 16, 1-18 (1936). 



J. H. Northrop, M. Kunitz, and R. M. Herriott: Crystalline Enzymes, 2nd ed., 

 Columbia University Press, New York (1948). 



S. B. KoRiK and H. Chantrenne: The relationship of ribonucleic acid to the in vitro 

 incorporation of radioactive glycine into the proteins of reticulocytes. Biochim. Biophys. 

 /^cfa 13,209-215 (1954). 



6. D. S. HoGNESS, M. CoHN, and J. Monod: Studies on the induced synthesis of /3-D- 

 galactosidase in Escherichia coli. The kinetics and mechanism of sulfur incorporation. 

 Biochim. Biophys. Acta 16, 99-116 (1955). 



7. P. N. CAiMPBELL and T. S. Work: The biosynthesis of protein. Uptake of glycine, serine, 

 valine and lysine by the mammary gland of the rabbit. Biochem. J. 52, 217-227 (1952). 

 B. A. AsKONAS, P. N. Campbell, and T. S. Work: The biosynthesis of proteins. Synthesis 

 of milk proteins by the goat. Biochem. J. 58, 326-331 (1954). 



B. A. Askonas, p. N. Campbell, C. Godin, and T. S. Work: Biosynthesis of Proteins. 

 Precursors in the synthesis of casein and )3-lactogIobulin. Biochem. J. 61, 105-115 (1955). 



C. Godin, and T. S. Work: Biosynthesis of proteins. The effect of intravenous peptides 

 on casein synthesis in a lactating goat. Biochem J. 63, 69-71 (1956). 



8. M. V. Simpson and S. F. Velick: The synthesis of aldolase and glyceraldehyde-3- 

 phosphate dehydrogenase in the rabbit. /. Biol. Chem. 208, 61-71 (1954). 



M. V. Simpson: Further studies on the biosynthesis of aldolase and glyceraldehyde-3- 

 phosphate dehydrogenase. J. Biol. Chem. 216, 179-183 (1955). 



9. M. Heimberg and S. F. Velick: The synthesis of aldolase and phosphorylase in rabbits. 

 J. Biol. Chem. 208, 725-730 (1954). 



S. F. Velick: The metabolism of myosin, the meromyosins, actin and tropomyosin in 

 the rabbit. Biochim. Biophys. Acta 20, 228-236 (1956). 



10. R. B. Loftfield and A. Harris: Participation of free amino acids in protein synthesis. 

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11. D. Steinberg and C. B. Anfinsen: Evidence for intermediates inovalb umin synthesis. 

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C. B. Anfinsen and D. Steinberg: Studies on the biosynthesis of ovalbumin. /. Diol. 

 Chem. 189,739-744(1951). 



10 



