An electrochemical biosensor for kinase activity could help in the search for new cancer treatments.
"The thiophosphorylation allows gold nanoparticles to bind to the peptide, and it is through the electrochemistry of these particles that kinase activity is determined. "
Heinz-Bernard Kraatz and Kagan Kerman at the University of Western Ontario in London, Canada, have used gold nanoparticles in an electrochemical approach to monitor kinase enzyme activity.
The technique is based on protein phosphorylation, a kinase-catalysed reaction in which a phosphate group is transferred from adenosine triphosphate (ATP) to a protein. In their approach Kraatz and Kerman follow kinase-catalysed thiophosphorylation, where a sulfur-containing ATP analogue, ATP-S, is used to transfer a thiophosphate group to a peptide immobilised on a carbon electrode. The thiophosphorylation allows gold nanoparticles to bind to the peptide, and it is through the electrochemistry of these particles that kinase activity is determined.
A kinase adds a thiophosphate group to a peptide (blue and red), allowing a gold nanoparticle to bind
Kraatz explained that kinases play a big part in cancer development due to the phosphorylation process. 'Phosphorylation can modify the function and/or the location of a protein and change its role in the signalling pathways within a cell,' he said. He highlighted the need for an adaptable method to assess the enzyme's activity. 'The systematic large-scale in vitro analysis of kinases in a rapid and high-throughput fashion using cost-effective and simple miniaturised devices is critical,' he said.
Phil Bartlett, professor of electrochemistry at the University of Southampton, UK, explained that a simple electrochemical method to determine kinase activity is an exciting development. 'It holds out the prospect of sensitive, cost effective, portable assays as well as the potential for in vivo kinase profiling,' he said. He added that, whilst the work needed further development, 'given the importance of kinase assays in the diagnosis of cancers and the screening of anticancer drugs this approach could contribute to a significant step forward in medical diagnostics and drug discovery.'