Frequently asked questions

Protein, detection & labeling

Protein, detection & labeling

iD Buffer composition

5x Sample Buffer

SDS-PAGE Native PAGE Final concentration (1x Buffer)
Tris base 300 mg 300 mg 50 mM
Glycerol 5.0 mL 5.0 mL 10%
Bromophenol blue 25 mg 25 mg 0.01 %
2-mercaptoethanol 1.0 mL 1.0 mL 2%
SDS 1.0 g - 2%
Deinonized water to 10 mL to 10 mL -
pH (use 8M NaOH or 8M HCl) 6.8 6.8 -

 Store at room temperature

1x protein sample solution:

Sample x µL
Sample Buffer 5x 2 µL
Deinonized water to 10 µL

Heat at 95°C for 10 minutes before loading on gel

10x MOPS Running Buffer: to separate medium to large proteins >20 kDa

SDS-PAGE Native PAGE Final concentration (1x Buffer)
Tris base 60.6 g 60.6 g 50 mM
MOPS 104.6 g 104.6 g 50 mM
EDTA 3.0 g 3.0 g 1 mM
SDS 10.0 g - 0.1 %
Deinonized water to 1000 mL to 1000 mL -
pH (do not adjust) 7.7 7.7 -

Store at 4°C up to 6 months

10x MES Running Buffer: to separate small proteins (2-50 kDa)

SDS-PAGE Native PAGE Final concentration (1x Buffer)
Tris base 60.6 g 60.6 g 50 mM
MES 97.6 g 97.6 g 50 mM
EDTA 3.0 g 3.0 g 1 mM
SDS 10.0 g - 0.1 %
Deinonized water to 1000 mL to 1000 mL -
pH (adjust with 8M NaOH or 8M HCl) 7.3 7.3 -

Store at 4°C up to 6 months

20x Transfer Buffer:

20x Transfer Buffer*
Tris base 60.6 g
Bicine 81.6 g
Deionized water 1000 mL

To make 1L of 1x transfer buffer: mix 50 ml of 20x transfer buffer, 100mL of methanol or ethanol and 850 mL of deionized water.