Whole Cell Protein and LPS Gels

Categorized: Protein Purification and Gel Electrophoresis


Hitchcock and Brown. 1983. Journal of Bacteriology, 154:269-277


This is a procedure analyzing LPS produced by bacteria, by using a protein-free LPS preparation and after gel electrophoresis, staining the gel using a LPS specific stain.


  • Lysing buffer:
  • 2% SDS
  • 4% 2-mercaptoethanol
  • 10% glycerol
  • 0.1 M Tris-HCl, pH 6.8


  1. Grow the bacteria overnight on appropriate agar plates.
  2. Harvest cells with A sterile loop and suspend in 0.9% saline to an OD600 of 0.4 (equivalent to 200 Klett units using a blue filter).
  3. Remove 1.5ml of the suspension and centrifuge in a microfuge for 1 1/2 minutes to pellet the cells.
  4. Solubilize the pellets in 100ul of lysing buffer.
  5. Heat the lysates to 100oC for 10 minutes.
  6. For protein digestion of the samples, add 25ug of proteinase K, solubilize in 10ul of the lysing buffer to each boiled lysate. Incubate at 60oC for 1 hour.
  7. Run the gel as usual and stain with silver (see the silver staining protocol).