Protein Constituents of Spermatozoa 93 



in special 'catalase tubes' in whichi hydrogen peroxide is added to 

 semen and the volume of evolved oxygen recorded. In ram sperma- 

 tozoa, even after mechanical disintegration, we were able to detect 

 only a very weak catalase activity: an extract from 0-2 g. sperm (wet 

 weight) required 20 min. at 18° to decompose a quantity of hydrogen 

 peroxide which would have been decomposed in 2 min. by 0001 ml. 

 blood. Sea-urchin semen on the other hand, contains much more 

 catalase (Evans, 1947; Rothschild, 1948c, 1950c; Barron, Gasvoda 

 and Flood, 1949; Rybak and Gustafson, 1952). 



The lack of catalase in mammalian semen explains the harmful 

 effects of hydrogen peroxide and pure oxygen on spermatozoa (see 

 p. 58). It is also of considerable physiological interest for another 

 reason, inasmuch as the spermatozoa themselves produce hydrogen 

 peroxide in vitro during the oxidation of certain amino-acids (see 

 p. 117). 



Hyaliironidase and other 'lytic' agents 



The term 'hyaluronidase' in its widest sense, designates the muco- 

 lytic enzyme, or rather a group of enzymes, which bring about the 

 depolymerization and hydrolysis of hyaluronic acid. The muco- 

 polysaccharide called hyaluronic acid is a polymer of the disac- 

 charide hyalobiuronic acid which consists of A^-acetylglucosamine 

 and D-glucuronic acid; its enzymic degradation, that is depoly- 

 merization and hydrolysis, is believed by Meyer and his school 

 (1937, 1952) to be due to the opening of the A^-acetylglucosaminidic 

 bonds. Thus it should be possible to assess the activity of hyalu- 

 ronidase by the determination of the reducing groups liberated by 

 the enzymic process. In actual practice, however, this is only possible 

 with the use of purified hyaluronidase since crude enzyme prepara- 

 tions often liberate additional reducing groups through the forma- 

 tion of free glucuronic acid and A^-acetylglucosamine by i^-glu- 

 curonidase and /S-glucosaminidase, respectively. Apart from the 

 'reductimetric' method, however, there are several other ways in 

 which the activity of hyaluronidase can be measured; among those 

 in use is the 'mucin clot prevention (m.c.p.) test' in which the preci- 

 pitation by acetic acid of the clot-like protein-hyaluronic acid 

 complex is prevented by the enzyme; the 'turbidimetric' method is 

 based on the observation that purified hyaluronate at pH 4-2, gives 



