3o6 



F. LIPMANN, L. C. TUTTLE 



VOL. 4 (1950) 



in an earlier table, the ester hydrolysis is much 

 more rapid as the condensation reaction and 

 very soon the tributyrin was split to com- 

 pletion. An appreciable exchange should, 

 however, have been shown by a considerable 

 increase of hydroxamate formation with the 

 ester. The values found (Table VI) are prac- 

 tically identical, due to the presence of nearly 

 equivalent amounts of butyrate during the 

 major part of the incubation period. In the 

 sample with tributyrin, the butyrate obviously 

 originated from hydrolysis. 



In similar experiments with equivalent 

 amounts of ethyl and sodium butyrate, similar 

 results were obtained. A slight increase of 

 hydroxamate formation was observed in the 

 earlier part of the incubation period, which 

 evened out, however, with the progress of 

 time. This may be due to a non-enzymatic 

 reaction of the ester with hydroxylamine, 

 recently observed under analogous conditions 

 by Chantrenne^^ or to a slow enzymatic exchange reaction. 



15 30 45 



TIME, MINUTES 



Fig. 3. Time curve of hydroxamic acid 

 formation. Conditions as in Fig. 2. 0.02 M 

 octanoate. 



TABLE VI 



COMPARISON OF EQUIVALENT AMOUNTS OF TRIBUTYRIN AND BUTYRATE 



0.1 ml of hog liver extract in 0.5 ml total volume, 0.6 M hydroxylamine. The tributyrin was diluted 

 with 9 volumes of 95% ethanol of which 0.0 1 ml was added. The same amount of ethanol was added 

 to the butyrate sample to equalize conditions. 



EXPERIMENTS WITH PANCREAS LIPASE PREPARATIONS 



In order further to check the ability of lipase to condense carboxyl groups with 

 hydroxylamine we turned to an exploration of the action of pancreas lipase on fatty acid 

 and hydroxylamine. As source of the enzyme, the marketed pancreatine of Parke-Davis 

 was used. The condensation with hydroxylamine was easily observed likewise with 

 pancreas enzyme, although somewhat less actively than with the liver enzyme. Sig- 

 nificantly, the chain length optimum was sh'fted to the longer chains in accordance 

 with the more truly lipatic nature of the pancreas enzyme. 



By using an untreated suspension of pancreatine a rather la^ge blank value was 

 obtained. Th's could, however, be reduced considerably by wash'ng with sl'ghtly ac'd 

 fluid. Generally, not too much activity went into solution in this manner. The residue 

 References p. 3og. 



