title: Enzymic activity at interfaces. II. Enzymic activity of microsomal nuclease and bovine pancreatic ribonuclease at the air/water interface.
abstract: The adsorption isotherms and the spreading tendency of microsomal nuclease (nucleate 3'-oligonucleotidohydrolase, EC 3.1.4.7) and bovine pancreatic ribonuclease (ribonucleate 3'-pyrimidino-oligonucleotidohydrolase, EC 3.1.4.22) in the presence of isopropyl alcohol as spreading agent have been determined using enzymes radioactively labelled by acetylation. In parallel, the concentration-surface pressure relations have been established. The enzymic activity of microsomal nuclease spread from isopropyl alcohol containing aqueous solutions was only a few percent of its activity in bulk, while the activity of the adsorbed enzyme was only slightly reduced. Adsorbed monolayers of RNAase were almost inactivated, while the spread monolayers in the presence of isopropyl alcohol became reactivated after exposure to the substrate for several hours. The exposure time for the reactivation decreases with increasing surface concentration.
mesh_terms: D000388:Air; D000818:Animals; D002417:Cattle; D007700:Kinetics; D008836:Micrococcal Nuclease / Q000378:metabolism*; D010179:Pancreas / Q000201:enzymology; D011312:Pressure; D012260:Ribonucleases / Q000378:metabolism*; D013499:Surface Properties; D014867:Water
chemical_list: D014867:Water; D012260:Ribonucleases; D008836:Micrococcal Nuclease