title: Biochemical assay by immobilized enzymes and a mass spectrometer.
abstract: By counting the volatile molecules produced by an immobilized-enzyme catalyzed reaction which is interfaced to a mass spectrometer via a semi-permeable membrane, a general approach to biochemical measurement and detection is obtained which offers the potential of high sensitivity, specificity and speed. In combination with molecule microscopy, this method should allow, for example, a mapping of suitable enzyme distributions in non-stained and non-fixed tissue slices. Immobilized urease (urea amidohyrdrolase, EC 3.5.1.5) was used to assay urea using CO2 as the volatile product, and alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) was used to assay NADH using ethanol as the volatile product.
mesh_terms: D000429:Alcohol Oxidoreductases / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis; D000431:Ethanol / Q000032:analysis; D013058:Mass Spectrometry / Q000295:instrumentation; D008567:Membranes, Artificial; D009243:NAD / Q000032:analysis; D011485:Protein Binding; D014510:Urease / Q000032:analysis*
chemical_list: D008567:Membranes, Artificial; D009243:NAD; D002245:Carbon Dioxide; D000431:Ethanol; D000429:Alcohol Oxidoreductases; D014510:Urease