Amersham Biosciences has responded to competition in the marketplace for purifying tagged proteins with the launch of Ni Sepharose, a new affinity chromatography medium.
The product is a nickel-based gel designed to separate and purify proteins and polypeptides labelled using the histidine-tagging (His-tag) approach pioneered by Eli Lilly. Ni Sepharose is precharged - in other words it does not have to be activated before use - which puts it on a par with its main competitor, the Ni-NTA product range sold by Qiagen of the Netherlands.
Amersham believes its product has an advantage over its rivals because it has a high capacity. This means that researchers can isolate more protein per millilitre of gel, so the amount of media can be reduced. As Amersham is pricing its product on a par with Ni-NTA, the cost of purifications should be lower.
Another advantage of Ni Sepharose is negligible leakage of nickel. This avoids contamination of the sample which in some cases could affect experimental results, she said. Negligible nickel leakage also minimises protein precipitation, which increases purity as well as yield.
Ni Sepharose is also compatible with a wide range of reducing agents, detergents, denaturants and other additives, she noted.
One of the primary applications of his-tagging is in structural genomics, where it is used to isolate proteins of interest from a sample - often in a high-throughput environment - in order to work out their three-dimensional structure. In these experiments, researchers start with cDNA clones, from which recombinant protein is produced and subsequently purified. The three dimensional structure of the proteins is then determined via either X-ray crystallography or nuclear magnetic resonance.
In addition to the lab product, Ni Sepharose is also available in pre-packed 1ml and 5ml columns that can be used with a syringe, a laboratory pump or chromatography systems, including Amersham's own äKTA range.
The spokeswoman noted that Amersham is in the process of negotiating a license with the Inproteo consortium, which holds rights to the His-tag technology. The latter recently started a push to secure licensing agreements with all organisations that make use of the technology.
Ni Sepharose is available in 25ml and 100ml packs, priced at €280 and €980, respectively. For more information, on the product, visit Amersham's website .