A spectrophotometric assay for the determination of 4-diphosphocytidyl-2-C-methyl-d-erythritol kinase activity

We report an assay for the determination of the activity of 4-diphosphocytidyl-2-C-methyl-d-erythritol kinase, the enzyme which catalyzes the fourth reaction step of the 2-C-methyl-d-erythritol 4-phosphate pathway for the synthesis of isoprenoids, which is based on the spectrophotometrical determination of adenosine 5′-diphosphate using pyruvate kinase and l-lactate dehydrogenase as auxiliary enzymes. This method can be adapted to microtiter plates, can be automated, and because of its simplicity and speed can be useful for the functional characterization of the enzyme and for the screening of inhibitors with potential antibiotic or antimalarial action.