title: Enzymatic hydrolysis of nylons: quantification of the reaction rate of nylon hydrolase for thin-layered nylons.
abstract: Nylon hydrolase degrades various aliphatic nylons, including nylon-6 and nylon-66. We synthesized a nylon-66 copolymer (M w = 22,900, M n = 7,400), in which a part of an adipoyl unit (32 % molar ratio) of nylon-66 was replaced with a succinyl unit by interfacial polymerization. To quantify the reaction rate of the enzymatic hydrolysis of nylons at the surface of solid polymers, we prepared a thin layer of nylons on the bottom surface of each well in a polystyrene-based micro-assay plate. The thickness of the nylon layer was monitored by imaging analysis of the photographic data. More than 99 % of the copolymer with thicknesses of 260 nm (approximately 600 layers of polymer strands) were converted to water-soluble oligomers by nylon hydrolase (3 mg enzyme ml(-1)) at 30 °C within 60 h. These results were further confirmed by TLC analysis of the reaction products and by assay of liberated amino groups in the soluble fractions. The degradation rate of the thin-layered nylon-6 was similarly analyzed. We demonstrate that this assay enables a quantitative evaluation of the reaction rate of hydrolysis at the interface between the solid and aqueous phases and a quantitative comparison of the degradability for various polyamides.
authors: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo, 671-2280, Japan.
authors: Keisuke
authors: K
authors: Nagai
authors: Kazuki
authors: K
authors: Iida
authors: Kimiaki
authors: K
authors: Shimizu
authors: Ryo
authors: R
authors: Kinugasa
authors: Motoki
authors: M
authors: Izumi
authors: Dai-Ichiro
authors: D
authors: Kato
authors: Masahiro
authors: M
authors: Takeo
authors: Kozo
authors: K
authors: Mochiji
authors: Seiji
authors: S
authors: Negoro
mesh_terms: D002855:Chromatography, Thin Layer; D006867:Hydrolases / Q000378:metabolism*; D006868:Hydrolysis; D009757:Nylons / Q000378:metabolism*; D061848:Optical Imaging; D013696:Temperature; D013997:Time Factors
chemical_list: D009757:Nylons; D006867:Hydrolases