Dextran sulfate 500 sodium salt

Dextran sulfate as a ready-to-use 50% stock solution (w/w) for molecular biology.

Dextran sulfate is a heparin-like polysaccharide that increases the hybridization rate of nucleic acids between 3 and 100 times, depending on the probe used. Dextran sulfate functions as an accelerant by excluding the nucleic acid from the volume of solution occupied by the polymer, thereby, increasing the effective probe concentration. However, dextran sulfate should only be used if the rate of hybridization or the amount of DNA is a limiting factor in identifying 'rare' sequences.

The effect of dextran sulfate is greatest for polynucleotides with >250 nucleotides. There is no effect for oligonucleotides <14 bases. The use is also of no advantage for the hybridization of bacterial colonies or plaques. In some circumstances it can even lead to a high background. Handling a dextran sulfate solution is also made more difficult by the high viscosity of the solution. The working concentration is 10%.

If aqueous dextran sulfate solutions are to be autoclaved, they must be buffered with e.g. sodium bicarbonate, to prevent decomposition during autoclaving.

Dextran sulfate sodium salts are soluble and stable in water. Dextran sulfate sodium salt consists of approx. 17% - 20% sulfur, which corresponds to approx. 2.5 sulfate groups per glucosyl residue.