Since glutamine and glutamate can be interconverted by the enzymes glutamine synthetaseGlutamate+ATP+NH3→Glutamine+ADP+Pi(3)and glutaminase,Glutamine+H2O→Glutamate+NH3(4)it is not surprising that their concentrations seem to rise and fall in unison in some tumour types. Here, GLS is linked to neoplasm.