MOPS: Difference between revisions
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[[Image:800px-MOPS.png|right|200px|thumb|chemical structure of MOPS, 3-(N-morpholino) propanesulfonic acid]] | [[Image:800px-MOPS.png|right|200px|thumb|chemical structure of MOPS, 3-(N-morpholino) propanesulfonic acid]] | ||
* | * 83.7 g MOPS; MW 209.3 g/mol | ||
* | * 13.6 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 | * 2.9 g EDTA, sodium salt; MW 292.2 g/mol | ||
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==Final concentration of active compounds in 10x stock== | ==Final concentration of active compounds in 10x stock== | ||
* | * 400 mM MOPS (buffering) | ||
* | * 100 mM NaAc | ||
* 10 mM [[EDTA]] (nuclease inhibition by Mg2+ chelation) | * 10 mM [[EDTA]] (nuclease inhibition by Mg2+ chelation) | ||
==Variation== | |||
Some protocols use a less concentrated MOPS buffer | |||
* 200 mM MOPS - 41.9 g in 1 L | |||
* 20 mM NaAc - 2.7 g | |||
* 10 mM [[EDTA]] - 2.9 g | |||
==Stability of MOPS== | ==Stability of MOPS== | ||
Revision as of 10:05, 2 March 2009
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
- 83.7 g MOPS; MW 209.3 g/mol
- 13.6 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
- 400 mM MOPS (buffering)
- 100 mM NaAc
- 10 mM EDTA (nuclease inhibition by Mg2+ chelation)
Variation
Some protocols use a less concentrated MOPS buffer
- 200 mM MOPS - 41.9 g in 1 L
- 20 mM NaAc - 2.7 g
- 10 mM EDTA - 2.9 g
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
- Jacobs:Protocol RNA Agarose Gel
- Knight:NuPAGE electrophoresis
- Sauer:bis-Tris SDS-PAGE, the very best
