Professor Kemp is recognised internationally as one of the major figures to contribute to our understanding of protein kinases at the molecular level and their roles in cellular signalling. Starting with the cAMP-dependent protein kinase in the mid-70's he delineated the substrate specificity of many different protein kinases and developed the novel simplifying concept that it depended on linear epitopes - one of which now bears his name as Kemptide. He also showed that an important common mechanism of kinase regulation was inhibition by a pseudosubstrate region of the kinase itself (intrasteric inhibition) that had to be modified to achieve activation of the kinase.