474 CHEMISTRY OF THE PROTEIDS CHAP. 



Heart of rat 



a A613-A596-5 

 ft A596-A563 

 y A556-A550 



The haematin-derivative occurring in the muscles of vertebrates, 

 is, according to MacMunn, a special 'myohaematin,' with definite 

 derivatives, all of which differ spectroscopically from ordinary haemo- 

 globin. Hoppe-Seyler, 1 Levy, 2 and Morner 3 are of the opinion 

 that the haemoglobin found in muscles is the same as that met with in 

 red blood -corpuscles, and that the displacement of the absorption 

 bands of muscle haemoglobin towards the red end of the spectrum [the 

 centre of the two bands of blood oxy haemoglobin being at A577 and 

 540, and those of myoheemoglobin at A581 and A543] does not signify 

 a difference in the haemoglobins. 



Morner 4 has suggested that the proteid-constituent of the pigment 

 may be different in haemoglobin and myohaematin. Halliburton 5 says : 

 " I think myself there can be no doubt that myohaematin is a deriva- 

 tive of haemoglobin, but whether the muscular tissue is capable of pro- 

 ducing the change in spite of the reagents added or whether the 

 reagents added are mainly responsible for the change, one cannot at 

 present say." 



Halliburton also quotes Copeman 6 who mixed defibrinated and 

 slightly diluted blood with minced muscle and kept it for three weeks 

 in the absence of air at 36, and so obtained the spectrum of myo- 

 haematin. On mixing blood with minced liver or other tissues Cope- 

 man obtained a haemochromogen-spectrum ; the myohaematin-bands 

 disappear when the myohaematin-solution is heated to near the boiling 

 point, according to Copeman and Halliburton. 



Since the globin radical may be replaced by egg-white as shown 

 by Ham and Balean see (p. 507), there is nothing against the con- 

 ception of haematin uniting with myosinogen or with other albumins 

 to form true respiratory pigments (Mann). 



The Crystals of Haemoglobin and Oxyhaemoglobin 



Oxy haemoglobin crystallises more readily than does any other 

 albumin, and has been known in its crystalline form for a very long 



1 F. Hoppe-Seyler, Zeitschr. f. physiol. Chem. 14. 106 (1889). 



2 L. Levy, ibid. 13. 309 (1888). 



3 K. A. H. Morner, Holy's Jahresber. f. Tierchemie, 27. 456 (1897), 



4 Morner, Nord. med. Ark. (Stockholm, Festband, 1897). 



g Halliburton, Biochemistry of Muscle and Nerve, 1904, p. 29. 



6 S. Monckton Copeman, Proc. Physiol. Soc. Nov. 8 (1890); and Journ. of 

 Physiol. 9. p. xxii. 



