Identification

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Storage Logistics

You provide us with a,b, or c:

a) Homogenous protein in an excised band from a dried SDS-gel (stained with Coomassie Blue or Silver, preferably without fixation). Please enclose a gel photo. Please mention the %age of the gel, clearly mark the band which was excised from the gel, and specify the molecular weight marker and the estimated molecular weight of the protein of interest.

b) Homogenous protein in an excised spot from a dried 2-D-Gel (stained with Coomassie Blue or Silver, preferably without fixation). Please enclose a gel photo. Please clearly mark the spot which was excised from the gel.

c) At least 5 µg purified native protein (ammonium sulfate precipitate or lyophilizd protein). Please enclose a gel photo (SDS-PAGE), mention the %age of the gel, clearly mark the band which corresponds to the purified protein, and specify the molecular weight marker and the estimated molecular weight of the protein of interest. Recommend a suitable buffer for dialyzing (ammonium sulfate precipitate) or dissolving (lyophilized material) the protein. If this is not a standard buffer, add your buffer in sufficient amount (esp. for dialysis). Mention special requirements of your protein with respect to solubility and stability (especially important for membrane proteins).

Required Information:

Source of the protein (organism, tissue, cell fraction etc.) and, if possible, any assumption about the nature and/or function of the protein of interest.
If available: Molecular Weight of protein and its subunits, and isoelectrical point.

Please ship the protein without cooling (dried gel bands or spots, lyophilized protein) or on blue ice (ammonium sulfate precipitate) to:

Gentaur bvba
Avenue de l'Armée 68/B4,  B-1040 Brussels

 
Our service:
  1. (In gel) trypsination of the protein (band or spot) of interest (protein is cleaved at arg and lys sites into peptides)
  2. MALDI-TOF Mass Spectometry analysis of the tryptic peptides
  3. Protein identification by computational tools (database searching combined with Bayesian statistics): Masses of peptides from the proteolytic digestion of the corresponding protein are compared to the masses of a peptide database based on the non redundant information extracted from NCBI, GenBank, CDS translations, PDB, SwissProt, PIR, and PRF protein databases. The result is a ranking of candidate proteins based on their calculated posterior probability. The protein identity is re-verified using pI, MW and peptide mass fingerprinting data and comparing them with the theoretical peptides calculated for all proteins of question in the SWISS-PROT/TrEMBL databases. This verification process is carried out by trained scientists who verify the protein identity by checking the peptide pattern peak by peak for plausibility taking trypsin autolysis and trypsin cleavage faults into account.
  4. You receive a detailed analysis report featuring the identity of the protein and the likelihood of the correctness of the identification. In case it is a new protein, the features of similar/related proteins are listed.
 
Order Information:

Cat. Nr. PIPB01: Protein Identification by MALDI-TOF-MS, protein shipped in protein gel band
Price: 500 $

Cat. Nr. PIPS01: Protein Identification by MALDI-TOF-MS, protein shipped in 2 D gel spot
Price: 500 $

Cat. Nr. PIPP01: Protein Identification by MALDI-TOF-MS, purified protein provided
Price: 570 $

Please note: In case the protein amount or purity was not sufficient to perform MALDI-TOF MS, a set up fee of € 175 is charged.

Protein Candidates
Rank
Probability
Protein Description
MW (kDa)
1
1.0e+00
gi|6324486|ref|NP_014555.1| Alcohol dehydrogenase; Adh1p [Saccharomyces cerevisiae]
37
2
3.2e-03
gi|1168350|sp|P00330|ADH1_YEAST ALCOHOL DEHYDROGENASE I
37
3
7.8e-09
gi|6324174|ref|NP_014244.1| Ynl155wp [Saccharomyces cerevisiae]
32
4
1.1e-09
gi|7245674|pdb|1YLV|A Chain A, Schiff-Base Complex Of Yeast 5-Aminolaevulinic Acid Dehydratase With Laevulinic Acid
38
5
3.9e-10
gi|171974|gb|AAA34790.1| (M81696) mitochondrial ribosomal protein [Saccharomyces cerevisiae]
29
6
3.2e-10
gi|6325350|ref|NP_015418.1| Ypr093cp [Saccharomyces cerevisiae]
36
7
3.0e-10
gi|223142|prf||0512226A dehydrogenase isozyme I,alcohol [Saccharomyces cerevisiae]
32
8
3.0e-10
gi|6320613|ref|NP_010693.1| 263-amino acid mitochondrial ribosomal large subunit protein; similar to L23 family of ribosomal proteins; Mrp20p [Saccharomyces cerevisiae]
31
9
1.2e-10
gi|626218|pir||S45958 probable membrane protein YBR090c - yeast (Saccharomyces cerevisiae)
13
10
1.2e-10
gi|6319560|ref|NP_009642.1| mitochondrial ADP/ATP translocator; Aac3p [Saccharomyces cerevisiae]
33
       
The contaminating protein was identified as alcohol dehydrogenase and could now be removed easily from the mixture by exploiting its known hydrophobicity (washing the column with isopropanol).
 
Our service:

Sample preparation and MALDI-TOF Mass Spectrometry of the protein. Determination of the absolute mass of the protein subunit(s).

 
Order Information:

Cat. Nr. DMW01
Absolute Molecular Weight Determination of purified protein by MALDI-TOF MS
Price: 225 $

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