Enhanced MALDI-TOF MS Analysis of Phosphopeptides Using an Optimized DHAP/DAHC Matrix
Figure 5
Tryptic digests of - (upper) and -casein (lower) (12.5–250 fmol on target) were detected with DHAP/DAHC (a) and (c) and DHB/PA (b) and (d) by MALDI-TOF MS in positive mode. DHAP/DAHC positions were selected randomly in the outer ring of the sample; for DHB/PA, only signals in hot spots were collected. In total, 200 profiles were accumulated for each sample. The number of sites on each phosphopeptide was equal to the number of asterisks ().