From OpenWetWare
Revision as of 09:54, 2 March 2009 by Jakob Suckale (talk | contribs)
Jump to: navigation, search
The other mops

MOPS is the common name for the buffering compound in MOPS buffer. MOPS stands for 3-(N-morpholino) propanesulfonic acid and with a pKa of 7.20, MOPS is an good buffer for many biological systems at almost neutral pH. HEPES is a chemically similar pH buffering compound.

Recipe for 10x MOPS buffer

chemical structure of MOPS, 3-(N-morpholino) propanesulfonic acid
  • 41.9 g MOPS; MW 209.3 g/mol
  • 2.7 g Sodium Acetate, trihydrate; MW 136.1 g/mol (watch out: NaAc, anhydrous is only 82 g/mol or 1.6g)
  • 2.9 g EDTA, sodium salt; MW 292.2 g/mol

  • add 800 ml of nuclease free distilled water; mix to dissolve
  • adjust to pH 7 with NaOH (prepared in nuclease free distilled water)
  • fill to the final volume of 1000 ml

  • filter sterilise or autoclave
  • store at room temperature
  • protect from light; do not use if the solution appears yellow

Final concentration of active compounds in 10x stock

  • 200 mM MOPS (buffering)
  • 20 mM NaAc
  • 10 mM EDTA (nuclease inhibition by Mg2+ chelation)

Note: Farrell uses higher concentrations for 10x stock: 400 mM MOPS, 100 mM NaAc, 10 mM EDTA

Stability of MOPS

Contrary to common belief, MOPS is sufficiently heat-stable to be autoclaved. Solution will turn yellow but this does not interfere with its buffering capacity. See, for example, Farrell RNA methods, p201 [1]. Straw coloured buffer is but do not use darker buffer.

Some OWW protocols which use MOPS

External links