title: A convenient test for lipase activity in aqueous-based solutions.
abstract: We proposed a convenient and accurate method for the measurement of lipase activity in a uniform aqueous-based substrate solution. In this work, lipase from Candida rugosa was used as the model lipase to test its catalytic ability toward p-nitrophenyl palmitate (p-NPP), which was suspended in a mixture of p-NPP ethanol solution and buffer. An ultraviolet-visible spectrophotometer was used to efficiently measure the liberated p-nitrophenol without extraction or centrifugation. Several factors that affected lipase activity were investigated, such as the ratio of p-NPP ethanol solution to buffer, the concentrations of p-NPP and lipase, as well as the temperature, reaction time, pH and agitation rate. Additionally, enzyme catalytic parameters such as Km, Vm and "activation energy" were also assessed. We determined the optimal conditions for lipase in this homogeneous system and demonstrated lipase's catalytic performance in this condition followed Michealis-Menten kinetics.
authors.affiliation: Key Laboratory of Eco-Textile (Jiangnan University), Ministry of Education, Wuxi, Jiangsu 214122, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Guo
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Cheng-Peng
authors.initials: CP
authors.lastname: Chen
authors.affiliation: Key Laboratory of Eco-Textile (Jiangnan University), Ministry of Education, Wuxi, Jiangsu 214122, China. Electronic address: wangshugen@163.com.
authors.forename: Shu-Gen
authors.initials: SG
authors.lastname: Wang
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: hxjzxh@zju.edu.cn.
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Huang
mesh_terms: D055162:Biocatalysis; D002021:Buffers; D002175:Candida / Q000201:enzymology*; D004789:Enzyme Activation; D000431:Ethanol; D005656:Fungal Proteins / Q000032:analysis / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007700:Kinetics; D008049:Lipase / Q000032:analysis / Q000378:metabolism*; D010168:Palmitates / Q000378:metabolism; D012996:Solutions; D013379:Substrate Specificity; D013696:Temperature; D013816:Thermodynamics; D014867:Water
chemical_list: D002021:Buffers; D005656:Fungal Proteins; D010168:Palmitates; D012996:Solutions; D014867:Water; C050015:4-nitrophenyl palmitate; D000431:Ethanol; D008049:Lipase
keywords: Candida rugosa lipase; Lipase enzymatic activity measurement; Uniform aqueous-based solution; p-nitrophenyl palmitate