An assay for carbonic anhydrase activity and reactions that produce radiolabeled gases or small uncharged molecules

An assay procedure for carbonic anhydrase activity is described. Unique to this method is the use of radiolabeled bicarbonate and a reaction vessel with a gas-permeable membrane. The method detects 14CO2 production directly and can be used at room temperature and with solutions buffered over a wide pH range. Assays are rapid (5-10 s), discounting elution and scintillation counting time. The equipment required is simple and inexpensive, marking the method ideal for routine determinations of carbonic anhydrase activity. The method can also be applied to other reactions that liberate radioactive CO2, other labeled gases, or small unchanged, labeled molecules.