Fructose and Fructolysis 155 



Adenosine triphosphate (ATP, formula in Fig. 15) represents an 

 intracellular constituent and a coenzyme of considerable importance 

 in the economy of the sperm cell. An observation that a considerable 

 proportion of the acid-soluble phosphorus in bull spermatozoa 

 yields orthophosphate after 7 min. hydrolysis with n-HCI first 

 suggested the presence of ATP (Lardy and Phillips, 1945). In the 

 same year, the readily-hydrolysable phosphorus compound was 

 isolated from ram spermatozoa and its identity with ATP estab- 

 lished by chemical analysis (Mann, 1945«, c); the content of ATP 

 in ram spermatozoa is 2-6-6-6 mg. labile phosphorus or 0-6-1 -5 mg. 

 of adenine amino-nitrogen per 100 ml. semen (see also Table 16). 

 The occurrence of ATP in ram and boar spermatozoa has also been 

 confirmed by Ivanov, Kassavina and Fomenko (1946) who found 

 that the phosphorus compound which they purified from sperm 

 induced contractions of muscle actomyosin threads in the same 

 manner as ATP isolated from skeletal muscle. ATP was also found 

 in sea-urchin spermatozoa (Rothschild and Mann, 1950), the con- 

 centration of ATP in the semen of Echinus escidentus resembling 

 that found in the ram. 



Spermatozoa, even after they have been repeatedly washed so as 

 to remove the phosphatases present in seminal plasma, continue to 

 exhibit a high phosphatase activity against ATP, and all evidence 

 available at present points to sperm ATP-ase as the enzyme which 

 is directly responsible for the supply of energy essential for normal 

 motihty and survival of the sperm cell. The losses due to utilization 

 of ATP are made good by re-synthesis which takes place during the 

 normal metabolism of spermatozoa, and any interference with inter- 

 mediary enzymic reactions which renders the sperm cell incapable 

 of breaking down or building up ATP, leads to a decrease in both 

 metabolism and motility. Using ram spermatozoa as experimental 

 material under a variety of conditions, we have found that a diminu- 

 tion in the content of ATP invariably coincides with impaired sperm 

 motility (Mann, 1945^7, b, c). Thus, for instance, in ram spermatozoa 

 deprived of the fructose-containing seminal plasma by washing, 

 ATP content as well as motility went down simultaneously on 

 anaerobic incubation, but both ATP and motility could be 

 preserved anaerobically in sperm suspensions provided with 

 glycoly sable material. 



