抄録
Polyethylene adipate (PEA)-degrading enzyme of Penicillium sp. strain 14-3 was purified by precipitation with ammonium sulfate and chromatography with CM-Sephadex C-50. The purified enzyme was confirmed to be homogeneous by ultracentrifugal analysis and polyacrylamide gel electrophoresis. Some properties of the purified enzyme were examined. The molecular weight of the enzyme was estimated by gel filtration on Sephadex G-100 to be approximately 25, 000. Optimum pH and temperature were around 4.5 and 45°C, respectively. The enzyme was stable up to 50°C and in a pH range from 4.0 to 10.0 on 5.5 hr incubation at 35°C. The enzyme was activated remarkably by Ca2+ and Cd2+. In substrate specificity, this enzyme degraded various kinds of saturated and unsaturated aliphatic polyesters and polycyclohexanedimethanol adipate as alicyclic polyester but not aromatic polyesters such as polytetramethylene terephthalate, polyethylene tetrachrolophthalate and poly-2, 2-dimethyl-trimethylene isophthalate. Bisphenol A polycarbonate, a polycarbonate resin, was also degraded. Polyesters with a few hybrid bonds among polymer chains were hardly degraded. A kind of terminal groups, such as hydroxy, hexahydrophthalic acid* and hexahydrophthalic acid glycidil ester** terminal did not affect so much on the enzyme activity. The enzyme further hydrolyzed various plant oils, triglycerides and methyl esters of fatty acid. Therefore PEA-degrading enzyme was assumed to be a kind of lipase.
