52 THE BACTERIAL PHOTOCHEMICAL APPARATUS 



47. Umbarger, H. E., Feedback control by endproduct inhibition. Cold Spr. 

 Harb. Synip. Quant. Biol., 26, 301 (1961). 



48. Burnham, B. F., Evidence for a negative feedback system in the control of 

 porphyrin biosynthesis. Biochem. Biophys . Res. Commun., 7,351 (1962), 



49. Burnham, B. F.,and Lascelles, J., Control of porphyrin synthesis through a 

 negative-feedback mechanismrstudies with preparations of 5-aminolaevulate 

 synthetase and dehydratase irom Rhodopseudomonas spheroides. Biochem. 

 J., 87,462 (1963). 



50. Lascelles, J., The synthesis of enzymes concerned in bacteriochlorophyll 

 formation in growing cultures of Rhodopseudomonas spheroides . J. Gen. 

 Microbiol., 23, 487 (1960). 



51. Wiame.J.M., Le role biosynthetique du cycle des acides tricarboxyliques. 

 Advan. Enzymol., 18, 241 (1957). 



Note added in proof ipa.ge 35). It has been learned that another 

 pigment designated as bacteriochlorophyll b, has been identified 

 spectroscopically in a Rhodopseudomonas sp. Its structure is 

 unknown (Eimhjellen, Aasmundrud, and Jensen, Biochem, Biophys. 

 Res. Commun., 10,232, 1963). 



