Peptide mapping of AMEL-2

One microgram of AMEL-2 were incubated in AMBIC 50 mM with 10 ng of Tryp / Lys-C (1:100) (Promega) in AMBIC (NH₄HCO₃) 50 mM at 37° C for 4 h. The peptide mixture obtained by proteolytic digestion was measured by MALDI-TOF (MALDI micro MX, Waters) using saturated CHCA matrix solution (Sigma Aldrich) in 50% ACN, 50% H₂O, 0.1% TFA. 1 μl of the peptide mixture was mixed with 1 μl of matrix on the spot of the sample holder plate. Mass spectra were acquired in positive linear or reflectron mode.