SOME ASPECTS OF BIOCHEMICAL DIVERSITY 303 



pigmentation of the teguments, feathers, scales, hair and eyes of the 

 chordates. A vital role for an enzyme of the phenolase type occurs during 

 the biosynthesis of adrenaline and noradrenaline, but this remains to be 

 clarified. 



"Each of the numerous heterotypic expressions of the phenolase complex 

 is produced by a unique biochemical sequence which is characterized by 

 (1) a phenolase specificity becoming narrower with rise in the phylogenetic 

 scale, (2) a characteristic chemical position in a metabolic network, and 

 (3) a specific physical localization within cell and organ. These variables 

 give ample play to the 'chance combination of genes which results in the 

 development of short reaction chains utilizing substances whose synthesis 

 had been previously acquired' (Horowitz, 1945), and to the states and 

 composition of the environment which determine the extent to which the 

 inherited phenolase complex can carry out its primary reaction. In this 

 manner, the chemical structure of an enzyme and its substrate can be 

 expressed as one of a number of biological characters." 



REFERENCES 



Florkin, M. (1948). La biologic des hematinoproteides oxygenables. Experientia, 



4, 176-191. 

 Goodwin, T. W. (1952). The Comparative Biochemistry of the Carotenoids, London, 



Chapman & Hall. 

 Granick, S. (1954). Metabolism of heme and chlorophyll. Chemical Pathivays of 



Metabolistn, edited by Greenberg, D. PvL, vol. II, New York, Academic 



Press, 287-342. 

 Haagen-Smith, a. J. (1953). The biogenesis of terpenes. Ann. Rev. Plant Physiol., 



4, 305-324. 

 Mason, H. S. (1955). Comparative biochemistry of the phenolase complex. 



Advanc. EnzymoL, 16, 105-184. 

 Pappenheimer, a. M. (Editor) (1953), The Nature and Significance of the Antibody 



Response, Columbia University Press, New York. 

 Wyman, J., Jnr. (1948). Heme proteins. Advanc. Protein Chem., 4, 407-531. 



