POLYSACCHARIDE-PROTEIN COMPLEXES 



209 



lipid (mainly neutral fat) 8.5 per cent, and ash 3 per cent, leaving 

 16 per cent unaccounted for by this procedure. Comparable data, 

 in agreement with the above, were reported by Roelof sen ( 1953 ) . 

 Not all of the nitrogen found in yeast cell-wall preparations is asso- 

 ciated with protein; many reports indicate the presence of chitin in 

 veast cell walls. Employing the chitosan sulfate microchemical tech- 

 nique, Roelofsen and Hoette ( 1951 ) demonstrated the presence of 

 chitin in bakers' yeast and other yeast species, thereby confirming 

 observations of Schmidt ( 1936) and Nabel ( 1939), who had claimed 

 the presence of chitin in yeast. 



Preparation of Isolated Clean Cell Walls of Yeast. By mechan- 

 ical disruption of bakers' yeast and Candida albicans, followed by 



Fig. 1, Cell-wall fragment obtained by mechanical disintegration and dif- 

 ferential centrifugation of Candida albicans. 



