Fig. 3
From: Preparation of uniformly labelled 13C- and 15N-plants using customised growth chambers
In each experiment high abundant isotopologues of tryptophan were represented as M (all carbons are 12C), M’ (all carbons are 13C) and M’’ (all nitrogens are 15N) and the low abundant isotopologues of the same molecule are M + 1 (one 13C and rest 12C), M’-1 (one 12C and rest 13C) and M’’-1 (one 14N and rest 15N). The relative isotopologue intensities were used to determine the degree of enrichment