Complex of N-terminal 6His-tagged recombinant, murine p110α full length, containing the mutation E542K, and untagged, recombinant, murine p85α full length. The E542K substitution is a somatic mutation in p110α that has been associated with tumours of the colon and brain. Combined in vitro and in vitro studies have shown that this mutation confers higher lipid kinase activity than wild type, and is able to induce oncogenic transformation. (Kang S. et al., PNAS, (2005);102: 802-807 and Zhao J.J. et al., PNAS, (2005);102:18443-18448).