ENZYMES CONCERNED WITH DIGESTION OF LIPIDS 63 



choline acetylase, Korey et al. m redefined it as "the enzyme apparently 

 specifically concerned with the transfer of acetate from the intermediate 

 product to choline." According to Nachmansohn and co-workers, 368 this 

 "intermediate product" is presumably acetyl coenzyme. These workers 

 reported that an enzyme prepared from pigeon liver extracts was able, in 

 the presence of ATP, to form acetyl coenzyme. The term "acetylkinase" 

 is proposed. Thiolacetate was shown to function in the full system in 

 place of ATP-acetate. In later investigations by Korkes and associates, 369 

 it was demonstrated that a partially purified choline acetylase, prepared 

 from squid head ganglia, brought about the synthesis of acet3'lcholine from 

 acetyl-CoA and choline, associated with the appearance of a stoichio- 

 metric amount of sulfhydryl groups. 



(c) Distribution of Choline Acetylase. Nachmansohn and Berman 370 

 reported, in 1946, that choline acetylase was present only in nerve tissue; 

 they were able to prove its occurrence, not only in the vertebrate nervous 

 tissue, but also in the nerves of invertebrates, in sensory nerves, and in 

 electric tissue. In contradistinction to this, the presence of the coenzyme 

 (acetyl-CoA) was demonstrated in brain, liver, heart, and skeletal muscle. 



Choline acetylase was obtained from the sciatic nerve of the rabbit b} r 

 Nachmansohn, John, and Berman. 175 A solution prepared from one gm. 

 of these nerve fibers caused the synthesis of 70 to 90 /ig. of acetylcholine 

 per hour, as compared with that of 150 to 200 Mg-/hr. when comparable 

 preparations from rat or guinea pig brains were employed. The active 

 enzyme was shown to be in that part of the neuron which does not contain 

 the nerve endings and cell bodies. This is considered as offering support 

 for the hypothesis that acetylcholine may be essential not only for the trans- 

 mission of the nerve impulse across the synapse but also for its propagation 

 along the axon. 



Later investigations demonstrated that choline acetylase is present in 

 tissues other than nervous tissue. Nachmansohn and co-workers 371 re- 

 ported the presence of the enzyme in pigeon breast muscle, in skeletal 

 muscle of the guinea pig, and in cardiac muscle of the rabbit. In no case 

 was any choline acetylase observed in liver or kidney extracts. Comline 



367 S. R. Korey, B. de Braganza, and D. Nachmansohn, J. Biol. Chen., 189, 705-715 

 (1951). 



368 D. Nachmansohn, I. B. Wilson, S. R. Korev, and R. Berman, J. Biol. Chem., 195, 

 25-35(1952). 



369 S. Korkes, A. del Campillo, S. R. Korev, J. R. Stern, D. Nachmansohn, and S. 

 Ochoa, /. Biol. Chem., 198, 215-220 (1952). 



370 D. Nachmansohn and M. Berman, /. Biol. Chen., 165, 551-563 (1940). 



371 D. Nachmansohn, M. Berman, and M. S. Weiss, ./. Biol. Chem., 167, 295-290 ( 1 947 ). 



