64 The Nature of Biological Diversity 



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Table 9. Formation of citrulline from carbamyl 

 phosphate and ornithine 



Species /umole citrulline/g powder 



R. productus (1) 187 



R. productus (2) 166 



H. calif ornicus 223 



M. calif ornicus 205 



G. marmorata 166 



Reaction mixture: 0.1 ml 0.1 M ornithine; 0.2 ml 0.2 

 M K-phosphate. buffer (pH 7.4) ; 2.5 ml 0.02 M dilith- 

 ium carbamyl phosphate; 0.8 ml water; 0.5 ml extract 

 of Type 1 powder. 

 Incubation : 30 min at 38°C. Readings at 490 nux. 



source: Baldwin (1958, 1960). 



Table 10. Formation of urea from citrulline and aspartate 



Species 



/imole urea/g powder 



Preformed After incubation Synthesized 



R. productus (1) 

 R. productus (2) 

 M. calif ornicus 

 G. marmorata 

 U. halleri 



126 158 27 



126 178 52 



95 118 23 



95 121 26 



74 108 34 



75 103 28 



123 145 22 



125 159 34 



126 158 32 



127 177 50 



Reaction mixture: 0.15 ml 1.0 M i.-citrulline; 0.15 ml 1.0 M aspartic 

 acid (K salt) ; 0.1 ml 1.0 M K-buffer (pH 7.4) ; 0.1 ml 0.066 M MgSO*; 

 0.1 ml 0.025 M ATP (K salt); 0.2 ml 0.1 M K-phosphoglycerate; 0.1 

 ml arginase (ca. 150 units/ml); 0.1 ml glycolysing enzyme preparation. 

 Incubation: 30 min at 38°C. Readings at 540 m^. 



source: Baldwin (1958. 1960). 



