120 



The Biochemistry of Semen 



(Morton, 1953). Methods for the purification of acid phosphatase 

 from human prostate glands and semen have been described by 

 London and Hudson (1953) and Boman (1954). 



Alkaline phosphatase, like the 'acid' enzyme, is widely distributed 

 in male accessory organs but its localization in cells and concentra- 

 tion in accessory gland secretions is different. Human semen with 

 its conspicuously high level of acid phosphatase, has a low concen- 

 tration of the alkaline phosphatase. Bull semen on the other hand, 

 has only slight acid phosphatase activity but contains more of the 

 alkaline phosphatase (Haq and Mullen, 1948; Reid, Ward and 

 Salsbury, 1948^). This difference between the human and bovine 

 semen is not altogether unexpected, since the bulk of bull seminal 

 plasma is derived not from the prostate but from the seminal 

 vesicles. In the rat both phosphatases are of low activity; with the 

 exception of the ventral prostate which may contain up to 20 units 

 of alkaline phosphatase per g. tissue, the level of either enzyme 

 seldom exceeds 4 units per g. in any one of the other accessory 

 organs. After castration the activity of both these enzymes diminishes 

 first in the rat seminal vesicles, and a little later in the prostate; but 

 the percentage decrease of enzymic activity and of organ weight is 

 roughly equal (Huggins and Webster, 1948; Stafford, Rubinstein 

 and Meyer, 1949). 



Table 17. Phosphatase activity of ram seminal plasma on 

 phosphohexoses (Mann and Lutwak-Mann, 19516) 



(The liberation of sugars was examined by incubating 5 mg. substrate 

 (Na salt) with 1 ml. dialysed seminal plasma at pH 7 or 0-2 ml. dialysed 

 seminal plasma at pH 9, for 1 hr., 37°, in the presence of OOOSM-MgCla. 

 The sugars were determined after deproteinization with ZnS04 and 

 Ba(OH)2; glucose was estimated by means of glucose oxidase (Mann, 

 1944; \9A6b).) 



