CHLOROFHYLL AND HEMOGLOBIN 235 



C — C. 

 the existence of the grouping ] / N in the molecule, since 



the two chief oxidation products are found to be pyrrole 

 derivatives of the formulae — 



CH,.C— C0\ CH3.C— C0\ 



'\ 



NH II )NH 



COOH . CH2 . CH„ . C— Co/ CH3 . CH., . C— Co/ 



Hffimatinic acid imide Methylethylmaleinimide 



The former substance, which is the imide of a tricarboxylic 

 acid known as hsematinic acid, of the formula — 



CH3.C— COOH 

 II 

 COOH . CH2 . CH2 . C— COOH 



has also been obtained from haemoglobin, the red colouring 

 matter of the blood, and a connexion between haemoglobin and 

 chlorophyll is thereby established. 



The relationship between this haematinic acid imide and 

 haemoglobin is as follows : — 



Haemoglobin is readily hydrolysed by dilute acids or 

 alkalis with the formation of haematin ; this latter substance 

 contains iron, which can, however, be readily removed by treat- 

 ment with hydrogen bromide in acetic acid solution,* giving 

 an iron free compound haematoporphyrin ; j- both haematin % 

 and haematoporphyrin on oxidation yield the haematinic acid 

 imide mentioned above. 



Another link between chlorophyll and haemoglobin is sup- 

 plied by the fact that Willstatter and Asahina § have obtained 

 from chlorophyll by reduction three pyrrole derivatives : — 



C2H5C=CCH3\ CaHsC^CCHjV CoH^C = CH \ 



I \nH I )NH I )NH 



CH3C = CCH.,/ CH,C = CH / CH3C = CCH3/ 

 Phyllopyrrole Hasmopyrrole Iso-haemopyrrole 



one of which, haemopyrrole, has also been obtained by the re- 

 duction of haematoporphyrin. 



With regard to the manner in which the magnesium or iron 

 are respectively united to the complex molecules of chloro- 



* Nencki and Zaleski: " Zeit. physiol. Chem.," 1900, 30, 423. 

 t It should be noted that chlorophyll derivatives free from magnesium are 

 by analogy called porphyrins ; cf. Phylloporphyrin, etc. 



:J:Kiister: "Zeit. physiol. Chem.," 1899,28, i; 1900, 29, 185. 

 § Willstatter and Asahina: " Annalen," 1911, 385, i!S8. 



