title: Enzyme reaction rates at limited water activities.
abstract: A well-mixed powder consisting of dry urea and urease exposed to air containing discrete amounts of water vapor showed a release of carbon-14 dioxide above 60-percent relative humidity. The relative activity of urease followed the water-vapor adsorption isotherm of urease. The minimum amount of water required for the reaction observed was 1.3 moles per mole of side-chain polar groups of the urease protein.
mesh_terms: D000327:Adsorption; D002247:Carbon Isotopes; D006813:Humidity; D007700:Kinetics; D014508:Urea / Q000378:metabolism; D014510:Urease / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D014508:Urea; D014510:Urease