Fig. 7.

FT-ICR MS analysis of the D-series of chemically modified Ocr. Upper panel, Ocr before (left-hand peak) and after (nested set of peaks) chemical modification with dimethylamine for 15 min as described in Methods. Middle panel, Ocr before (left-hand peak) and after (nested set of peaks) chemical modification with dimethylamine for 60 min. Lower panel, Ocr before (left-hand peak) and after (nested set of peaks) chemical modification with dimethylamine for 180 min. In each case, the [M + 12H]¹²⁺ charge state was analysed. The number in italics is the average m/z value for unmodified Ocr. The number in bold signifies the number of Δ+27 Da modifications for each species.