• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Analytical Biochemistry: An International Journal of Analytical and Preparative Methods >Surface dilution kinetics using substrate analog enantiomers as diluents: Enzymatic lipolysis by bee venom phospholipase A_2
【24h】

Surface dilution kinetics using substrate analog enantiomers as diluents: Enzymatic lipolysis by bee venom phospholipase A_2

机译：使用底物类似物对映体作为稀释剂的表面稀释动力学：蜂毒磷脂酶A_2的酶促脂解

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A novel assay employing d-enantiomers of phospholipids as diluents for characterizing surface kinetics of lipid hydrolysis by phospholipases is introduced. The rationales of the method are (i) d-enantiomers resist hydrolysis because of the stereoselectivity of the enzymes toward l-enantiomers and (ii) mixtures of l+d-lipids at various l/d ratios but constant l+d-lipid concentrations yield a surface dilution series of variable l-lipid concentration with constant medium properties. Kinetic characterization of bee venom phospholipase A_2 activity at bile salt+phospholipid aggregate-water interfaces was performed using the mixed l+d-lipid surface dilution assay, and interface kinetic parameters were obtained. The assay applies to biomembrane models as well. Activity was measured by pH-stat methods. Aggregation numbers and interface hydration/microviscosity measured by time-resolved fluorescence quenching and electron spin resonance, respectively, confirmed that interface properties were indeed invariant in a surface dilution series, supporting rationale (ii), and were used to calculate substrate concentrations. Activity data show excellent agreement with a kinetic model derived with d-enantiomers as diluents and also that d-phospholipids bind to the enzyme but resist hydrolysis; underscoring rationale (i). The assay is significant for enabling determination of interface-specific kinetic parameters for the first time and thereby characterization of interface specificity of lipolytic enzymes.
机译：介绍了一种新颖的测定方法，该方法使用磷脂的d对映异构体作为稀释剂来表征磷脂酶水解脂质的表面动力学。该方法的原理是：（i）d-对映体抵抗水解，因为酶对l-对映体具有立体选择性;（ii）各种l / d比率但l + d-脂质浓度恒定的l + d-脂质混合物产生具有恒定介质特性的可变I脂质浓度的表面稀释系列。用混合的l + d-脂质表面稀释法对蜂毒磷脂酶A_2在胆汁盐+磷脂聚集体-水界面的活性进行了动力学表征，得到了界面动力学参数。该测定法也适用于生物膜模型。活性通过pH-stat方法测量。通过时间分辨的荧光猝灭和电子自旋共振分别测量的聚集数和界面水合/微粘度证实界面性质在表面稀释系列中确实是不变的，支持了原理（ii），并用于计算底物浓度。活性数据显示出与以d-对映异构体为稀释剂的动力学模型完全吻合，并且d-磷脂与酶结合但抗水解。强调理由（i）。该测定对于首次确定界面特异性动力学参数并由此表征脂解酶的界面特异性具有重要意义。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号