52 



Scientific Proceedings (117). 



cystin isolated by the Folin method was 7 per cent., while the 

 lime method gave a yield of 6.3 per cent. 



24 (i77i) 



A globulin as the principal protein of the pecan nut : Its chemical 

 and nutritive properties. 



By F. A. CAJORI (by invitation). 



[From the Department of Chemistry, Stanford University, California.] 



Pecan meal, prepared by removing the oil from the whole 

 shelled nut, was extracted with 10 per cent, sodium chloride 

 solution. This extract containing the proteins of the meal was 

 subjected to fractional precipitation with ammonium sulfate and 

 fractional coagulation by heat. The results indicate that the 

 large part of the protein of the pecan nut is a globulin. This 

 globulin has been isolated and purified and the distribution of 

 its nitrogen determined by the Van Slyke method. Large amounts 

 of basic amino-acids were found to be present in this globulin. 

 It gives a strongly positive test for tryptophane. In general the 

 analysis agrees fairly well with the recently published results of 

 Dowell and Menaul 1 on mixed pecan proteins. 



Normal growth has been observed in young rats on diets in 

 which the protein of the ration was derived from the pecan nut, 

 indicating that this nut furnishes adequate quantities of those 

 nitrogenous complexes necessary for growth. In order to render 

 pecan nut diets suitable as rations for rats, it was found necessary 

 to remove the outer layer of the nut since this layer contains 

 large amounts of tannin. Previous failure to observe normal 

 growth in rats on pecan nut diets may be ascribed to the injurious 

 or distasteful effect of the tannins that were present in those diets, 

 and not to an inadequacy of amino-acid yield of the protein of 

 this nut. 



1 Dowell, C. T. f and Menaul, P., J. Biol. Chem., 1921, xlvi, 437. 



