1. prepare 100 ml of a 0.02M phosphate-buffered saline (PBS) from the following stock solutions:
1.9 ml of 0.2 M NaH2PO4xH2O,
1.2. 8.1 ml of 0.2 M Na2HPO4xH2O,
1.3. 0.9 g NaCl,
1.4. 80 ml ddH2O,
1.5. Adjust pH to 7.4,
1.6. Complete volume to 100 ml.
2. Prepare a microtubule Stabilization Buffer containing:
2.1. HEPES buffer (25 mM, pH 6.8),
2.2. 25 % glycerol,
2.3. 0.5 mM MgCl2,
2.4. 25 µM phenylmethyl sulfonyl fluoride (PMSF),
2.5. 1 % Triton X-100,
2.6. 0.01 % sodium azide.
All molarities and % given as final concentrations.
HEPES (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid) is a zwitterionic organic chemical buffering agent. It is widely used in cell culture media for maintaining a physiological pH level. PMSF is a serine protease inhibitor which is best prepared as a stock solution of 25mM PMSF in ethanol. Triton X-100 is a detergent, so it should be added to the buffer only after adjusting the pH. Sodium azide is a common preservative of samples and stock solutions, acting as a bacteriostatic.