218 



KoNR.AD Block 



Table III 



Isotope Concentrations in Amino-acids Obtained from Yeast Protein 

 AFTER Incubation with Labelled Glucose and Acetate 



Yeast grown on a medium containing [1-"C] glucose and [carboxy-^^C] acetate. 



Table IV contains the ^*C concentrations of various carbon 

 atoms in phenylalanine and tyrosine. The ingenious degra- 

 dation procedures of Baddiley, Ehrensvard et al. (1950) were 

 employed to establish the isotope distribution in the benzene 

 rings. These methods take advantage of the fact that carbon 

 atoms of the benzene ring which carry a nitro substituent 

 will yield bromopicrin {CBr3N02) on oxidation with hypo- 

 bromite, while ring carbons not so substituted will be oxidized 



Table IV 



Distribution of ^*C in Phenylalanine and Tyrosine from Yeast Grown 



ON [1-"C] Glucose 



Total 



COOH 



Qa (calc.) . . . 



C3 



Benzene ring: 



(a) calc 



{b) Picric acid 



(c) 2:4-Dinitroaniline 



^1,3,5 



^2,6,4 



^2,6 



C4 (calc.) .... 



