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Service offered: MALDI-TOF mass analysis of the peptide
mixture, database searches and protein identification:
The facility's Applied Biosystems Voyager-DE PRO MALDI-TOF mass
spectrometer can be used for the analysis of peptides, small
molecules, and whole proteins.
One of the major uses of the instrument is analysing peptides from
protein digests to identify the protein. A band or spot can be cut
from a 1D or 2D gel, the protein digested in-gel, and after Zip-Tip cleanup, the peptides are analyzed with
the mass spectrometer.
Peptide Mass Analysis:
- The sample plate with up to 100 spots is inserted in the mass
spectrometer
- A laser is applied to individual spot thus ionizing molecules of the
matrix which in turn transfers a proton to the peptides.
- Peptides are accelerated through the flight tube under vacuum and
in most cases in a reflector mode, which basically makes the flight
path longer than the actual tube.
- Peptides arrive at the detector based on their mass
to charge ratio (m/z).
- Using calibration peptides, the actual masses of the
peptides are assigned.
Data base search and Protein Identification:
All the masses that represent peptides from the original protein
(in other words, masses present in control samples where no protein
was present are ignored) represent the fingerprint of the protein in
question. By searching a mass database for protein fingerprints, the
protein is identified if known. If we are dealing with an unknown
protein, further identification becomes necessary among which is
peptide sequencing of selected peptides by post source decay (PSD) or
Collision induced dissociation (CID).
Data Provided: Actual mass profile (chromatogram) and data
from Mass search (protein identity). Extra data will include PSD and
CID (only upon request)
Turn-around time: 5-7 working days
Cost: On-campus (Protein identification) $150.00
Off campus (protein identification) $300.00
On and off campus (PSD/CID) $100.00
       
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