Fig. 6.

Amount of incorporation arising from glucose when erythrose is present for all amino acids. Both from individual (1-¹³C, 2-¹³C, 3-¹³C, and 4-¹³C erythrose, 1-¹³C glucose, and 2-¹³C glucose) and combined (1-¹³C glucose with 2-¹³C erythrose, 2-¹³C glucose with 3-¹³C erythrose) labeling approaches the amount of incorporation from glucose could be determined. The amount arising from erythrose is the complementary fraction. This scenario uses 2 g/l glucose and 2 g/l erythrose. Backbone carbonyl incorporation behaves differently. Whenever results from all other positions of an amino acid are in agreement with each other only one value per amino acid is shown. If certain positions of amino acids show significantly different behaviour than the rest they are shown right from the amino acids and are labeled according to their position (for Met, His, Trp, Phe and Tyr)