title: Effects of Pulsed Electric Field (PEF) Treatment on Enhancing Activity and Conformation of α-Amylase.
abstract: To explore an efficient, safe, and speedy application of pulsed electric field (PEF) technology for enzymatic modification, effects of PEF treatment on the enzymatic activity, property and kinetic parameters of α-amylase were investigated. Conformational transitions were also studied with the aid of circular dichroism (CD) and fluorescence spectra. The maximum enzymatic activity of α-amylase was obtained under 15 kV/cm electric field intensity and 100 mL/min flow velocity PEF treatment, in which the enzymatic activity increased by 22.13 ± 1.14% compared with control. The activation effect could last for 18 h at 4 °C. PEF treatment could widen the range of optimum temperature for α-amylase, however, it barely exerted any effect on the optimum pH. On the other hand, α-amylase treated by PEF showed an increase of Vmax, t1/2 and ΔG, whereas a decrease of Km and k were observed. Furthermore, it can be observed from fluorescence and CD spectra that PEF treatment had increased the number of amino acid residues, especially that of tryptophan, on α-amylase surface with enhanced α-helices by 34.76% and decreased random coil by 12.04% on α-amylase when compared with that of untreated. These changes in structure had positive effect on enhancing α-amylase activity and property.
authors.affiliation: College of Food Science, Southwest University, Chongqing, 400715, China.
authors.forename: Mei-ling
authors.initials: ML
authors.lastname: Tian
authors.affiliation: College of Food Science, Fujian Agriculture and Forestry University, Fujian, 350001, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Fang
authors.affiliation: College of Food Science, Southwest University, Chongqing, 400715, China.
authors.forename: Mu-ying
authors.initials: MY
authors.lastname: Du
authors.affiliation: College of Food Science, Southwest University, Chongqing, 400715, China. zfsswu@163.com.
authors.forename: Fu-sheng
authors.initials: FS
authors.lastname: Zhang
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects; D002942:Circular Dichroism; D004560:Electricity; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013050:Spectrometry, Fluorescence; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D000516:alpha-Amylases
keywords: Enzymatic kinetic; Enzymatic structure; PEF; Storage stability; α-Amylase