Autoflex 2 maldi tof tof

Molecular weight analysis was done using an Autoflex II MALDI TOF/TOF
(Bruker Daltonics).
hBfl-1 was incubated in
the absence and in the presence of hNOXA and 130E7
in a 1:2 ratio for 2 h. For mass spectroscopy analysis, equal volumes
(2 μL) of each sample dissolved in the reaction buffer (16 mM
phosphate, 50 mM NaCl, pH = 6.5) and MALDI Matrix solution (sinapic
acid; 20 mg mL^–1 in 50% acetonitrile -0.1% trifluoroacetic
acid solution) were cocrystallized on the MALDI target plate and allowed
to air-dry for 10 min. Mass spectra were acquired and processed with
FlexAnalysis 2.4. The control protein molecular weight spectra as
well as the protein and peptide conjugated spectra are shown. The
protein mass shift correlating to peptide molecular weight was observed
in a conjugated sample. The data were further processed using the
FlexAnalysis peak picking method. With our current instrumentation
and these experimental conditions, we expect on average a variation
in the observed molecular mass of about ±50 Da, depending on
the presence of slightly different ionization states of side chains,
the presence of different numbers of nature of counterions, etc.