452 ANIMAL BIOCHEMISTRY 



Anabolism may be regarded as the reversal of the general processes 

 of the figure. Although not all metabolic reactions are individually 

 reversible, the majority are, and in many of the other cases separate 

 routes are known for going in both directions. Thus a diet deficient 

 in certain amino acids may still allow the animal to draw on fat or 

 carbohydrate and a nitrogen source for synthesis of the missing amino 

 acid. Conversely, animals on diets of protein, vitamins, and minerals 

 use part of the protein for energy, part as a source of necessary amino 

 acids, and part for conversion to fats and carbohydrates. 



The anabolism and catabolism of lipides, proteins, and nucleic 

 acids are discussed in the next two chapters. General aspects of metab- 

 olism, respiration, and the energy content of foods are covered in 

 Chapter 21. 



REFERENCES 



Chemical Pathways of Metabolism. Edited by D. M. Greenberg. Academic Press, 



New York, 1955. 

 Pathways of Carbohydrate Metabolism in Microorganisms. I. C. Gunsalus, B. L. 



Horecker, and W. A. Wood. Bacteriological Reviews, 19, 79-128 (1955). 

 Dynamic Aspects of Biochemistry , third edition. E. Baldwin. Cambridge University 



Press, Cambridge, England, 1957. 

 Outlines of Enzyme Chemistry, second edition. J. B. Neilands and P. K. Stumpf. 



John Wiley & Sons, New York, 1958. 



