R. IIRRKLL 



This does not, of course, invalidate the statement by Rothschild, Cosi and 

 Meyers on the " importance of the vinyl groups of ferriprotoporphyrin in the 

 production of the new compound'. This has been emphasized elsewhere. 

 'Addition of two vinyl groups to give protoporphyrin . . . increased tre- 

 mendously the sensitivity of the molecule to irradiation' ^i. But this does not 



Table 3. The absorption bands of the pyridine hemochromes of 

 ferriprotoporphyrin and irradiation products 



negate the conclusion that the figures in Table 3, as well as those on the 

 irradiation of protoporphyrin, suggest a conversion to an oxyporphyrin type 

 of compound, without alteration of the side chains. 



/ wish to thank Dr. J. E. Falk for his interest in these investigations. 

 My thanks also go to those members of the Radiochemical Laboratory, University 

 ofN.S.W., who have helped me on numerous occasions. 



REFERENCES 



iDresel, E. I. B. and Falk, J. E. (a) Biochem. J . 63 (1956) 72 



(b) ibid. p. 80 



(c) ibid. p. 388 



^Shemin, D. in Currents in Biochemical Research: Interscience Publishers, Inc., New 



York, 1956 

 ^Hamilton, H. B., Okada, S. and Morrison, M. Biochim. biophys. acta, 23 (1957) 



540 

 *TiRRELL, R. Proceedings of the Symposium on the Peaceful Uses of Atomic Energy in 



Australia 1958 — in press 

 ^Lemberg, R. and Legge, J. W. Hematin Compounds and Bile Pigments: Interscience 



Publishers, Inc., New York, 1949 

 sBrohult, G. Nova Acta Soc. Sci. upsal 12, No. 4 (1940). Quoted by Bacq and 



Alexander ^- 



' Pickles, E. G. and Anderson, R. S. /. gen. Physiol. 30 (1947) 83 

 * Alexander, P. and Charlesby. A. Nature, Land. 173 (1954) 578 

 ^Rothschild, Mary-Louise, Gosi, Laura and Meyers, L. S. Nature, Lond., 182 



(1958) 316 

 ioLemberg, R. and Falk, J. E. Biochem. f. 49 (1951) 675 

 uRarron, E. S. G. and Johnson, Phyllis. Radiation Res. 5 (1956) 290 

 I'^Bac^, Z. M. and Alexander, P. Fundamentals of Radiobiology: Butterworths 



Scientific Publications, London, 1955 



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