Spermine, Choline, Ergothioneine 171 



resistant to acid hydrolysis and no choline was set free from it after 

 an hour's hydrolysis with N-H2SO4 (100^), long enough for glyceryl- 

 phosphorylcholine, to release all its choline in a free form. On the 

 other hand, under the influence of the prostatic secretion the com- 

 pound yielded equivalent amounts of choline and inorganic phos- 

 phate. All these facts pointed to the identity of the compound with 

 phosphorylcholine, a substance previously isolated from beef liver 

 (Inukai and Nakahara, 1935). Lundquist sought to obtain proof by 

 preparing the calcium salt; this he found to be identical with the 

 calcium salt of pure phosphorylcholine, C5Hi304NPClCa-4H20, 

 obtained synthetically by the method of Plimmer and Burch (1937). 



O 



HO— P— O -CHoCHa-N^ 



I " /|\ 



O ChJ CHp 



CH 



Phosphorylcholine 



The distribution of phosphorylcholine in the human reproductive 

 organs has not been investigated in detail, but Huggins and Johnson 

 (1933) have good evidence that the bulk of the phosphorus present 

 in the human seminal plasma is derived from the vesicular secretion. 

 From this Lundquist infers that phosphorylcholine is formed in the 

 seminal vesicles, and that the dephosphorylation is initiated at 

 ejaculation, as a result of contact between the prostatic secretion 

 which contributes the 'acid' phosphatase, and the vesicular secretion 

 which provides the substrate; the optimum pH for the dephos- 

 phorylation of phosphorylcholine by the prostatic phosphatase 

 measured in acetate buffer solutions is about 6-3 (Lundquist, 1947a, 

 b). It is of some interest to recall here the claim put forward by 

 Kutscher and Sieg (1950) that preparations of both the 'acid' and 

 the 'alkaline' phosphatases contain pyrophosphorylcholine as a 

 characteristic constituent. However, Roche and his colleagues (1952) 

 were unable to detect any cophosphatase activity in pure, synthe- 

 tically prepared pyrophosphorylcholine. 



The possibility that compounds other than phosphorylcholine 

 may act as precursors of free choline in semen was indicated already 

 by the earlier observation of Kahane and Levy that the quantity of 



