ANTI-ENZYME IMMUNITY 343 



hydrolysis and the development of turbidity were almost parallel, while 

 at pH 9.3 the hydrolysis was considerably faster than the increase in 

 turbidity. The latter was explained by assuming that the hydrolysis of 

 the phospholipid is the primary action, and that the aggregation of fat 

 globules to which the turbidity is due is dependent on this hydrolysis 

 but influenced by the physical conditions of the reaction mixture. 



Following the course of the hydrolysis of lecithin by toxin and iden- 

 tifying the reaction products, they found that the aqueous solution 

 of the hydrolysate contained practically all of the original lipid phos- 

 phorus in an organic form, and an equivalent amount of nitrogen, but 

 no free choline. The hydrolytic products were characterized as phos- 

 phorylcholine and a diglyceride. 



Lecithinase 

 a — Lecithin 



CHgOC — C17H5 



O 



+Hp CHsOC-Ci.Has + 



O 



CH2OH 



Oleyl-stearyl-diglyceride 



N on-hemolytic 



HO— P— O-CH^CHsNCCHgDa 



^\ I 



O OH OH 



Choline-phosphoric acid 



Zamecnik, Brewster and Lipmann (1947) reported that CI. welchii 

 lecithinase is completely inactive against phosphatidylserine, sphingo- 

 myelin*, ox brain cerebrosides, glycerophosphoryl choline and soy bean 



* According to MacFarlane (1948) the toxic cukure fihrates of CI. welchii contain 

 a lecithinase which is probably identical with the main lethal component of the fil- 

 trates, the a-toxin. This lecithinase did not hydrolyze cephalin but did hydrolyze 

 slowly sfhingomyelin. The CI. welchii toxins were observed to manifest the peculiar 

 specificity in s-plitting off fhos-phorylcholine from lecithin and sphingomyelin but 

 failing to attack cephalin or glycero-phos'phorylcholine and lysolecithin. 



