Ruiz_1999_Int.Biodeterior.Biodegradation_43_43

Two polyester polyurethane (PU)-degrading enzymes from Pseudomonas chlororaphis, 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 extracellular, soluble proteins with molecular weight of 63,000 Da and 31,000 Da. The 63,000 Da protein exhibits both esterase and protease activities toward r-nitrophenylacetate and hide powder azure respectively. The enzyme has anoptimum 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 r-nitrophenylacetate, butyrate and propionate,and has an optimum pH of 8.5. In addition, the enzyme activities of both proteins are heat stable after 10 min at 100 C and are inhibited 50% by the addition of 1 mM phenylmethylsulfonylfluoride indicating both are serine-hydrolases