A novel colorimetric assay for α-methylacyl-CoA racemase 1A (AMACR; P504S) utilizing the elimination of 2,4-dinitrophenolateElectronic supplementary information (ESI) available: Experimental details including synthesis of compounds, kinetic plots, inhibitor testing. See DOI: 10.1039/c7cc00476a

α-Methylacyl-CoA racemase (AMACR; P504S) regulates branched-chain fatty acid degradation, activates Ibuprofen and is a recognised cancer drug target. A novel, facile colorimetric assay was developed based on elimination of 2,4-dinitrophenolate. The assay was used to test 5 known inhibitors, determining IC 50 and K i values, reversibility and characterizing irreversible inhibition. A versatile continuous colorimetric assay for AMACR is reported.