Protein kinases play a vital role in regulating protein activation and cellular signalling by transferring a phosphate group from ATP (Adenosine 5'-triphosphate).
This phosphorylation process plays an important part in the progression of cancer and inflammatory diseases making kinases an important drug target.
Cisbio has licensed BellBrook's Transcreener assay technology to enable it to develop a universal kinase assay for use with its HTRF (homogenous time resolved fluorescence) system that works by detecting the ADP (Adenosine 5'-diphosphate) byproduct that is produced as a result of protein phosphorylation.
"This technology is a good complement to the technologies that we already have and helps round out our offering .
As it i s totally universal, with this one single assay users can address all kinases," said François Degorce, head of HTRF marketing and business development at Cisbio.
"HTRF was first validated on protein kinases 10 years ago.
Since then, we have implemented different systems so that we can now address over 160 different kinases.
This system assesses the generation of ADP by consumption of ATP by the kinase."
Cisbio's HTRF system combines time-resolved fluorescence (TRF) and fluorescence resonance energy transfer (FRET) to create a technique that takes advantage of a Europium cryptate complex's ability to transfer excitation energy to an acceptor molecule, such as allophycocyanin, when they are brought into close proximity with one another.
When such fluorophores are brought together by a biomolecular interaction a portion of the energy captured by the cryptate during excitation is transferred to the acceptor and then released as a FRET signal.
The FRET signal is therefore specific when the biomolecular event takes place.
The principle of the assay involves the cryptate labelled monoclonal antibody anti-ADP, and ADP coupled to the acceptor.
In this competitive immunoassay the binding of these two conjugates is displaced by free ADP.
This enables entire families of enzymes to be screened using exactly the same detection reagents, significantly minimising assay development time if the proteins or substrates are difficult to tag.
"Sometimes the enzymes can be difficult to isolate, or the substrates are not easy to synthesise and this is a very elegant and efficient way to measure something that is produced at the same time as the phosphorylated substrates.
You're not quantifying the phosphorylated substrate per se, but you are measuring the generation of ADP which tightly correlates to the enzyme activity," said Degorce.
BellBrook does supply a TR-FRET version of this assay themselves, but have licensed the ADP detection method out to be able to reach a wider range of clients though Cisbio.
Cisbio will be launching its own version of the technology using its proprietary fluorescence technologies in January 2008 at a similar price point to its other assay offerings.
"Interest from our customers [for this product] is very strong and it will be used mainly in primary kinase screening applications.
It may also be used in mechanistic studies as it gives access to different kinetic parameters," said Degorce.