250 



SCIENCE 



[N. S. Vol. XXVII. No. 



These protamines, of which salmine, 

 clupeine, scombrine and sturine are types, 

 ax'e composed chiefly of diamine acids. 

 Thus, as Kossel and Dakin^^ have shown, 

 sahnine contains 89.2 per cent, of its 

 nitrogen as arginine, 4.3 per cent, as pro- 

 line, 3.25 per cent, as serine, and 16.5 per 

 cent, as valine; a total of 98.4 per cent. 

 Similarly, scombrine contains 88.82 of its 

 nitrogen as arginine, 3.8 per cent, as pro- 

 line, and 6.8 per cent, as alanine; a total 

 of 99.42 per cent. Sturine, on the other 

 hand, differs from the two preceding pro- 

 tamines in that in addition to arginine it 

 contains fairly large amounts of histidine 

 and lysine. Prom these statements it is 

 plain to see that the basic character of 

 protamines with their large content of 

 diamino acids is much more marked than 

 that of ordinary proteins, such as are 

 found in somatic nucleoproteins. In some 

 species of fishes, the spermatozoon nucleus 

 contains in place of protamine a histone, as 

 the basic substance joined to the nucleic 

 acid. The significant point in this state- 

 ment is that the histones as a class eon- 

 tain less (about 31-38 per cent.) of their 

 total nitrogen in the form of diamino 

 acids (arginine, lysine and histidine), 

 while the majority of the protamines have 

 84-89 per cent, of their total nitrogen in 

 this form. Obviously, therefore, the basic 

 portion of the nucleoprotein is subject to 

 decided variation in the sperm of different 

 species of animals, although all are alike in 

 being made up in large measure of diamino 

 acids. 



The nucleic acids present in the sperma- 

 tozoon, as in the nuclei of somatic cells, 

 are composed of a condensed phosphoric 

 acid to which are joined the purine bases 

 adenine and guanine, the pyrimidine deri- 

 vatives thymine and probably cytosine, 

 with pentose and hexose groups in addition 



" Zeitschrift fiir physiologischen Chemie, Band 

 40, p. 565; Band 41, p. 407, and Band 44, p. 342. 



thereto. As expressed by Burian,^^ the 

 two purine bases are joined directly to the 

 phosphorus of the condensed phosphoric 

 acid, so that in all probability a phosphoric 

 acid amide-like combination results. The 

 thymine and cytosine -are presumably 

 joined with carbohydrate groups, the latter 

 being in turn bound mth the phosphoric 

 acid skeleton after the fashion of an ester. 

 Regarding the cytosine, it is not yet clear 

 whether this substance is a primary com- 

 ponent of nucleic acid or a secondary de- 

 composition product of the purine bases. 

 In any event, we have in the sperm nucleic 

 acid a complex substance containing phos- 

 phorus in the form of phosphoric acid, ni- 

 trogen in the form of purine bases and 

 pyramidine derivatives, together with car- 

 bohydi-ate in the form of- pentose and 

 hexose groups. In the sperm nucleus, this 

 acid is combined with a protein, such as 

 protamine, and according to the analyses 

 of Miescher the head of the ripe sperma- 

 tozoon of the salmon is composed of about 

 95 per cent, of a neutral salt of salmine 

 nucleate. These are important facts, since 

 they show us something as to the nature of 

 the chemical complex which constitutes the 

 active part of the spermatozoon, and which 

 of necessity plays an important role in the 

 synthetical and constructive processes con- 

 nected with fertilization of the egg and 

 with the later processes of cell division. 

 The dominance of the diamino acids in the 

 protein part of the nucleoprotein (as in 

 salmine) and the corresponding dominance 

 of purine (and pyrimidine) nitrogen in the 

 acid part of the nucleoprotein must im- 

 press us as significant when it is remem- 

 bered that this material is of necessity con- 

 cerned in the construction of cell, and 

 later, of tissue protoplasm. In making 

 these statements, I have no desire to mini- 

 mize in any degree the value of other 



" " Chemie der Spermatozoen," II., Ergeinisse 

 der PhyHologie, Band 5, p. 803, 1906. 



