Purification and characterization of two polyurethanase enzymes from Pseudomonas chlororaphis

Two polyester polyurethane (PU)-degrading enzymes from Pseudomonas chlorora phis, a bacterium that utilizes polyester PU as the sole carbon and energy source, were purified to electrophoretic homogeneity as indicated by sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE). Both enzymes are ex tracellular soluble proteins with molecular weight of 63,000 Da and 31,000 Da. The 63,000 Da protein exhibits both esterase and protease activities to ward rho-nitrophenylacetate and hide powder azure respectively. The enzyme has an optimum pH of 8.5 for esterase activity and an optimum pH of 7.0 for protease activity. The 31,000 Da protein exhibits esterase activity toward rho-nitrophenylacetate, butyrate and propionate, and has an optimum pH of 8.5. In addition, the enzyme activities of both proteins are heat stable af ter 10min at 100 degrees C and are inhibited 50% by the addition of 1 mM ph enylmethylsulfonylfluoride indicating both are serine-hydrolases, (C) 1999 Elsevier Science Ltd. All rights reserved.