<prompt> The drug imatinib acts by inhibtion of-The drug imatinib acts by inhibtion of-Glutathione reductaseThymidile synthetaseProtein kinase  <response>: Ans. is a i.e. Tyrosine kinase Imatinib inhibits tyrosine protein kinase in CML and the ones that are activated by platelet derived growth factor PDGF receptor, stem cell receptor and C-KIT receptor found in gastrointestinal stromal tumour GIST. 