The proportion of 13C and 12C isotopic forms of selected proteins is depicted for the wild type and the clpP mutant in the soluble and nonsoluble fraction; (exp. growth phase, transient phase (0 h), 5 h, 10 h, 15 h, and 20 h of stationary phase). The isotopic proportions of the soluble and nonsoluble fraction were calculated by normalization against the sum of all isotopic values for each protein in a fraction .