THE T.KCITniNS 423 



Cobra lecithinase has recently been sho\vn to liave an isoelectric point of 



8.5-8.6 as determined by electroplioretic studies, and a molecular weight 



of 31,600; this figure was established from data on the rate of diffu- 

 gion.109.110 



Lecithinase B, which causes the hydrolysis of both fatty acid residues 

 from the glycerol and leaves glyceryiphosphorylcholine, has been reported 

 in extracts from rice hulls, ^" as well as hi the venom of the bee (Apidae), 

 hornet (Vespa crahro), and wasp {Vespidae)}'^^ Fairbairn,"^ who has 

 isolated this enzyme from the clay mold, Penicillium notatum, calls it 

 "lysophospholipase." In addition to acting on lysolecithin, this ferment 

 causes the breakdown of lysocephalin. Schmidt, Hershman, and Thann- 

 hauser^^*^ demonstrated that this enzyme was also present in beef pan- 

 creas; these workers were able to isolate a-glycerylphosphorylcholine 

 after beef pancreas had been incubated at 37°C. for 3 hours. A simul- 

 taneous disappearance of a large part of the preformed phosphatides was 

 noted; this is presumptive evidence that the isolated diester originated 

 from enzjmiic hydrolysis of lecithin. Kahane and Levy^'^ have sho^^^l 

 the presence in rat intestines of a lecithinase B which hydrolyzes lecithin 

 to fatty acids, and to a water-soluble choline derivative which contains 

 glycerophosphate. The properties of the crude fraction obtained b}^ 

 Kahane and Levy are similar to those of the glyceryiphosphorylcholine of 

 Schmidt et al^^^ The latter workers have also sho\^ii that lecithin dis- 

 appears during the autolj^sis of minced rat intestine concomitantly with the 

 appearance of glyceryiphosphorylcholine and free choline. King and 

 Aloisi^-^ have likewise isolated a water-soluble choline ester of glycero- 

 phosphoric acid from beef pancreas. This compound had a ratio of glycero- 

 phosphate : choline of 1 : 2. 



Although little is kno\\'n of lecithinase C, which splits choline from the 

 lecithin molecule, the role of lecithinase D has become more important in 

 \'iew of the recent demonstration of its presence in the gas bacillus (Clos- 

 tridium welchii)}-^ This enzyme Avas found to decompose lecithin into 

 phosphocholine and a diglyceride. It is believed to be the specific or- 

 toxin which is the lethal, hemolytic, and necrotic substance present in the 

 filtrates of type A cultures. Protective sera have an activity which is 



1" A. Contardi and A. Ercoli, Arch. sci. biol. Italy, 21, 1-44 (1935). 



"5 S. Belfanti, Z. Immunitats., 56, 449-463 (1928). 



"8 D. Fairbairn, J. Biol. Chem., 173, 705-714 (1948). 



1" G. Schmidt, B. Hershman, and S. J. Thannhauser, /. Biol. Chem., 161, 523-.=i:ifi 

 (1945). 



118 E. Kahane and J. Levy, Compt. rend., 219, 431-433 (1944). 



1" G. Schmidt, L. Hecht, and S. J. Thannhauser. Cited from S. J. Thannhauser and 

 G. Schmidt, Physiol. Revs., 26, 310 (1946). 



120 E. J. King and M, Aloisi, Biochem. J., 39, 470-473 (1945). 



"1 M. G. MacFarlane and B. C. J. G. Knight, Biochem. J., 35, 884-902 (1941). 



