Download Ammonium Acetate BioChemica A3674

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Ammonium Acetate BioChemica
Synonym
Essigsäureammoniumsalz state of matter
Solid Solubility (20°C)
1480 g/L (H2O) Melting point
114°C Formula
CH3COONH4 M
77.08 g/mol CAS-No.:
631-61-8 HS-No.:
29152900 EC-No.:
211-162-9 Storage:
RT LGK:
10 - 13 Disposal:
14 WGK:
1 Specification
Assay (titr.)
min. 98 % pH (5 %; H2O)
6.5 - 7.3 (25°C) Heavy metals (as Pb)
max. 0.001 % Insoluble matter
passes test Water
max. 2.5 % Chloride
max. 0.002 % Sulfate
max. 0.005 % A (1 cm/1 M in H2O)
260 nm
max. 0.03 280 nm
max. 0.02 A3674
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Ammonium Acetate BioChemica
A3674
Literature
(1) Okayama, H. & Berg, P. (1982) Mol. Cell. Biol. 2, 161-170 High-efficiency cloning of full-length cDNA.
(2) Wallace, D.M. (1987) Methods Enzymol. 152, 41-48 Precipitation of nucleic acids.
(3) Ausubel, F.A., Brent, R., Kingston, R.E., Moore, D.D., Seidman, J.G., Smith, J.A. & Struhl, K. (eds.) (1995)
Current Protocols in Molecular Biology, Pages 15.3.1-4 (Suppl. 17) Greene Publishing & Wiley-Interscience, New
York.
(4) Saporito-Irwin, S.M. et al. (1997) BioTechniques 23, 424-427 Protocol for the preparation of plasmid
DNA, suitable for the transfection of mammalian cells.
Comment
All references describe methods for the precipitation of nucleic acids using ammonium acetate (NH4OAc),
instead of the commonly used sodium acetate. Stock solutions are made of 10 M (ref. 3; 770 g/L, filtered) or 7.5 M
ammonium acetate (4).
Precipitation of DNA: Make the DNA-containing sample 2.5 M ammonium acetate by adding 0.5 volume 7.5 M
ammonium acetate stock solution. Mix well and add 2.5 to 3 volumes (DNA-sample + ammonium acetate) ethanol
(example: 1 ml DNA-containing sample + 0.5 ml ammonium acetate; mix well; add 3.75 to 4.5 ml ethanol). Mix well
and incubate for 10 minutes in a dry ice bath or a -70°C freezer. Nucleotides and oligonucleotides will not be
precipitated, which will coprecipitate with the DNA, if sodium acetate is employed. Two consecutive precipitations
will remove 99 % of the nucleotides and result in a DNA recovery of more than 90 %.
The quality of the DNA resulting from this protocol is sufficient for the transfection of mammalian cells. The
preparation is much cheeper than the purification with cesium chloride (3).
Caution! Ammonium acetate shall not be used, if the purified DNA has to be phosphorylated, because ammonium
ions will inhibit the kinase.
Precipitation of RNA: Add to a 10 ml aqueous RNA-containing sample 0.1 volume 3 M NH4OAc (pH 5.5; 1 ml;
final conc. 0.3 M) and mix. Then add 27.5 ml (2.5 volumes) ethanol and mix. Incubate the sample for 10 minutes at
-70°C in a dry ice bath or a freezer. Ammonium acetate can be a substitute for potassium acetate, when the RNA is
used in a cell-free translation system.