Enzymatic hydrolysis of nylons: quantification of the reaction rate of nylon hydrolase for thin-layered nylons
Enzymatic hydrolysis of nylons: quantification of the reaction rate of nylon hydrolase for thin-layered nylons
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DOI：
10.1007/s00253-014-5885-2
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发表时间：
2014-10-01
影响因子：
5
通讯作者：
Negoro, Seiji
中科院分区：
文献类型：
--
作者：
Nagai, Keisuke;Iida, Kazuki;Negoro, Seiji
尼龙水解酶降解各种脂肪族尼龙，包括尼龙-6和尼龙-66。我们合成了尼龙-66共聚物（M（w）= 22，900，M（n）= 7，400），其中尼龙-66的一部分己二酰基单元（32%摩尔比）通过界面聚合被琥珀酰基单元取代。为了量化尼龙在固体聚合物表面的酶促水解的反应速率，我们在基于聚苯乙烯的微量测定板中的每个孔的底部表面上制备了一薄层尼龙。尼龙层的厚度通过对照片数据的成像分析来监测。超过99%的厚度为260 nm的共聚物（约600层聚合物股线）在30 ℃下在60小时内通过尼龙水解酶（3 mg酶ml（-1））转化为水溶性低聚物。这些结果通过反应产物的TLC分析和可溶性级分中释放的氨基的测定进一步证实。类似地分析了薄层尼龙-6的降解速率。我们证明，该测定能够定量评价在固相和水相之间的界面处的水解反应速率，并定量比较各种聚酰胺的降解性。
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 A degrees 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.