PRELIMINARY INVESTIGATIONS FOR A STUDY 

 OF ENERGY UTILIZED BY THE SURVIVING 

 FOWL ERYTHROCYTE IN H^M SYNTHESIS 



C. RIMINGTON 



From the work of Rittenberg, Shemin, Altman and others 

 in the field a fairly clear picture is emerging of the origin of 

 the various constituent atoms of the porphyrin ring of hgem 

 and this work has made possible speculations as to the actual 

 molecules involved in biosynthesis. One need only refer to 

 the schemes put forward by Lemberg and Legge (1949), 

 Wittenberg and Shemin (1950), and Neuberger, Muir and 

 Gray (1950). 



That hsem biosynthesis can take place in surviving erythro- 

 cytes in vitro is a discovery of first importance and makes 

 possible an attempt to investigate the system contributing 

 the necessary components and energy for this synthesis. 



I wish to report some preliminary experiments in this 

 direction carried out with Mr. Bufton some time ago. 

 Heparinized fowl blood was used, incubated with ^^N labelled 

 glycine in presence of streptomycin and penicillin for 24 

 hours at 37°, the isolated hsemin being eventually analysed 

 for ^^N content. 



The effect w^as first studied of increasing amounts of added 

 15^ glycine. Maximal incorporation was achieved at a level 

 of about 2 mg./ml. of blood suspension, in agreement with 

 Shemin's (1948) finding, and this quantity was therefore 

 used throughout subsequent experiments. 



Since experiments upon erythrocytes, in which inhibitors 

 or nutrilites are added to the system, are complicated by the 

 presence of the cell membranes, the effect of haemolysis was 

 next studied. When sufficient saponin was added to produce 



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