Multiplex analysis of enzyme kinetics and inhibition by droplet microfluidics using picoinjectors
作者:Staffan L. Sjostrom、Haakan N. Joensson、Helene Andersson Svahn
DOI:10.1039/c3lc41398e
日期:——
Enzyme kinetics and inhibition is important for a wide range of disciplines including pharmacology, medicine and industrial bioprocess technology. We present a novel microdroplet-based device for extensive characterization of the reaction kinetics of enzyme substrate inhibitor systems in a single experiment utilizing an integrated droplet picoinjector for bioanalysis. This device enables the scanning of multiple fluorescently-barcoded inhibitor concentrations and substrate conditions in a single, highly time-resolved experiment yielding the Michaelis constant (Km), the turnover number (kcat) and the enzyme inhibitor dissociation constants (ki, ki′). Using this device we determine Km and kcat for β-galactosidase and the fluorogenic substrate Resorufin β-D-galactopyranoside (RBG) to be 442 μM and 1070 s−1, respectively. Furthermore, we examine the inhibitory effects of isopropyl-β-D-thiogalactopyranoside (IPTG) on β-galactosidase. This system has a number of potential applications, for example it could be used to screen inhibitors to pharmaceutically relevant enzymes and to characterize engineered enzyme variants for biofuels production, in both cases acquiring detailed information about the enzyme catalysis and enzyme inhibitor interaction at high throughput and low cost.
酶动力学和抑制对包括药理学、医学和工业生物加工技术在内的众多学科都很重要。我们展示了一种基于微滴的新型装置,利用集成的生物分析微滴喷射器,在一次实验中对酶底物抑制剂系统的反应动力学进行广泛表征。该装置可在一次高度时间分辨的实验中扫描多种荧光编码的抑制剂浓度和底物条件,从而得出迈克尔常数(Km)、周转次数(kcat)和酶抑制剂解离常数(ki、ki′)。利用该装置,我们确定了 β-半乳糖苷酶和荧光底物 Resorufin β-D-galactopyranoside (RBG) 的 Km 和 kcat 分别为 442 μM 和 1070 s-1。此外,我们还研究了异丙基-β-D-硫代半乳糖苷(IPTG)对β-半乳糖苷酶的抑制作用。该系统有许多潜在的应用,例如可用于筛选药物相关酶的抑制剂,以及表征用于生物燃料生产的工程酶变体,在这两种情况下,都能以高通量和低成本获取有关酶催化和酶抑制剂相互作用的详细信息。