Photokinetic microassay of adenylate kinase using the firefly luciferase reaction

A new rapid photokinetic method is described for determining the activity of adenylate kinase (ATP:AMP phosphotranspherase, EC 2.7.4.3) in 0.1--5.0 micrograms of freeze-dried tissue. This represents a weight range far below that obtainable by fine-needle biopsy. The reaction 2 ADP in equilibrium with AMP + ATP was employed and the ATP formed assayed with firefly luciferase as light yielder. The light emission was recorded on a multi-channel scaler. The adenylate kinase activities found in tissues of mice were in the same range as previously described in a study using fluorometric microassay.