ENZYMES CONCERNED WITH DIGESTION OF LIPIDS 57 



increased from 250 to 500 grams. The total content of this enzyme was 

 likewise unchanged by denervation; however, the concentration was 

 doubled when the muscle weight was reduced to half by atrophy. Pseudo- 

 cholinesterase was shown to account for a maximum of only 5% of the total 

 esterase activity of either normal or denervated muscle. The content of 

 tributyrin ali-esterase decreased roughly in proportion to the loss in weight 

 of the atrophic muscle. 331 



Anfinsen 332 reported that a high degree of cholinesterase activity obtains 

 in areas of bovine retina which are rich in synaptic material. Cholinester- 

 ase in this tissue would be expected, in view of the fact that the retina is 

 phylogenetically derived from the brain. Rat and human skin, also, has 

 been shown by Thompson and Whittaker 333 to contain true (e) cholinester- 

 ase. Esterases which hydrolyze tributyrin and methyl butyrate are also 

 present in rat skin. 



e'. Cholinesterases in Snake Venom: Many snake venoms are potent 

 sources of cholinesterases. Iyengar and his co-workers, 334 in 1938, were 

 the first to note that cobra venom contains an acetylcholine-splitting en- 

 zyme. The enzyme was found to be 100 times more active than that found 

 in the electric organs of the electric ray {Torpedo occllata) nb and of the elec- 

 tric eel (Electrophorus (Gymnotus) electricus) , 336 which had previously been 

 considered to be the most concentrated source. Zeller 164 showed that cobra 

 cholinesterase is a separate type, which he describes as the c-type (see 

 page 29). The specificity of cobra cholinesterase has recently been de- 

 scribed by Mounter. 337,338 Chaudhuri 339 and Ghosh 204 have demonstrated 

 the presence of cholinesterase in the toxic secretion of the yellow-banded 

 krait (Bungarus fasciatus), as well as in a wide variety of snakes of the 

 Colubridae family. The potencies of the cholinesterase isolated from vari- 

 ous members of the Colubridae are listed in Table 6. 



Cholinesterase, however, has been shown to be entirely absent from the 

 venom of the rattlesnake (Crotalus terrificus) , 204 the sand-burrowing viper 

 (Echis carinatus) , 204 the "daboia" or Russell's chain- viper of India (Vipera 



332 C. B. Anfinsen, /. Biol. Chem., 152, 267-278 (1944). 



333 R. H. S. Thompson and V. P. Whittaker, Biochem, J., 38, 295-299 (1944). 



334 N. K. Iyengar, K. B. Sehra, B. Mukerji, and R. N. Chopra, Current Sci. (India), 7, 

 51-53 (1938). 



336 A. Marnay, Compt. rend. soc. biol, 126, 573-574 (1937). 



336 D. Nachmansohn, R. T. Cox, C. W. Coates, and A. L. Machado, /. Neurophysiol., 

 5, 499-515 (1942). 



337 L. A. Mounter, Biochem. J., 49, xlv-xlvi (1951). 

 S38 L. A. Mounter, Biochem. J., 50, 122-128 (1951). 



339 D. K. Chaudhuri, Ann. Biochem. Exptl. Med. (India), 4, 77-86 (1944). 



