100 PIERRE H. GONSE 



Certain explanations for this striking difference in cells from dif- 

 ferent groups of animals but otherwise of the same type will be con- 

 sidered below. It can be seen that if their respective equipment in 

 oxidative enzymes is very much alike, the difference must appear at 

 the level of energy conservation, namely in the efficiency of the 

 coupling of phosphorylation to oxidation. 



The data are presented in three parts. First, the results are given 

 of a qualitative survey of cytochromes and other respiratory en- 

 zymes in the spermatozoa of the dog, bull, and marine mollusk, 

 Spisula. In a second section, the proportions, concentration, and 

 turnover numbers of enzymes are tabulated, and comparisons are 

 made among spermatozoa and between these and body cells of the 

 parent organism. Finally, the data pertaining to enzymic activity in 

 relation to certain substrates and specific inhibitors are presented 

 and correlated with motility of the cells. 



EXPERIMENTAL PROCEDURES 



Biological Material 



Freshly collected bull semen, diluted about five times with 

 skimmed milk, was received weekly from a nearby artificial breed- 

 ing cooperative (Southeastern Pennsylvania Artificial Breeder's Co- 

 operative). During transportation and prior to use, the samples were 

 maintained at 10°C. The same three donor bulls were used through- 

 out (H 43, H 47, H 51). Spermatozoa numbered 50 to 200 X 10 s per 

 ejaculate, and the motility ratings given by the Cooperative were 50 

 to 80%. For spectrophotometric experiments the sperm suspensions 

 were washed three times, at 20°C, with a modified Ringer of pH 7.2 

 (NaCl 0.1 Ml, KC1 0.006M, MgSO, 0.002M, Na 2 HP(J 4 0.016M) keep- 

 ing the original dilution so far as possible. Centrifugations were run 

 at 1000 rpm for 20 minutes. The final working dilution was 5 to 

 10 X 10 8 cells /ml as estimated by turbidimetric and microscopic 

 methods. Fair motility was retained for a few hours in the saline 

 medium supplemented with glucose. 



Dog semen was obtained at the University of Pennsylvania Medi- 

 cal School and studied immediately after collection. The number of 

 spermatozoa per ejaculate was only 5 to 10 X 10 s ; therefore, semen 

 from five dogs had to be pooled and concentrated by one or two 



