We accept samples prepared from customers but they have to meet some requirements. Please read recommendations below:
For HPLC protein and peptide purification:
- Samples submitted should be free of non-volatile buffer components if possible.
- For special needs, columns and separation methods should be provided by users.
For 2-D gel protein separation:
- For analytical purposes, as little as 50 µg protein is needed. For preparative purposes, more than 1 mg protein can be loaded. The amount of sample depends on the complexity and the purpose of research.
- Salts, residue buffer components, and other charged small molecules should be removed. The tolerance for salts is 10 mM.
- Use zwitterionic or non-ionic detergents to increase protein solubility.
- Samples rich in nucleic acids should be treated with protease-free DNase/Rnase.
- Polysaccharides, lipids, and phenolic compounds should all be removed if possible.
For mass spectrometry:
- Use volatile, salt-free solvents such as methanol and acetonitrile.
- Salts normally form adduct peaks which suppress the molecular ion signal. Exchange sodium and potassium for ammonium when possible. Avoid phosphate buffers, use minimum concentrations of ammonium bicarbonate or ammonium acetate to control pH
- Avoid glycerol, DMSO, SDS, urea and guanidine. If detergents must be used, octyl glucoside (0.1%) is the best choice.
We also provide the following services:
- Protein extraction using phenol followed by methanolic ammonium acetate precipitation.
- For better homogenization of samples, the samples can be ground using the TissueLyser II
- For removing contaminants and interfering substances: TCA acetone precipitation, C18 or C4 micro-reversed-phase chromatography (Zip-tipping) Centrifugal filter and Perfect Focus 2D clean-up.