title: Activated effect of lignin on α-amylase.
abstract: This paper reports a new kind of activator of α-amylase, lignin, which can greatly increase α-amylase activity. The promoted ratio of lignin is even much higher than that of chloride ion, the traditional activator of α-amylase. Further experimental results reveal that lignin may interact with α-amylase to form a 1:1 complex with a binding constant of 4.47×10(5) M(-1). The binding is spontaneous and lignin/α-amylase complex formation is an exothermal reaction. Hydrogen bonding plays a key role and non-radiation energy transfers from α-amylase to lignin in the binding process. Lignin, combining with α-amylase, conforms to a first-order exponential decay function. The formation of the lignin/α-amylase complex results in the reduction of α-helical content from 57.7% to 53.9%, the increase of the polarity around tryptophan residues, the decrease of the hydrophobicity, and the enlargement of protein granule volume. This work will give a deeper insight into lignin as a kind of dietary fibre, known as an important food functional factor. Furthermore, it also contributes to the exploration of an activator of α-amylase, used in the food industry.
authors.affiliation: School of Life Sciences, Shanghai University, Shanghai 200444, PR China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.forename: Jun-Hui
authors.initials: JH
authors.lastname: Cui
authors.forename: Tingting
authors.initials: T
authors.lastname: Yin
authors.forename: Lizhou
authors.initials: L
authors.lastname: Sun
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D020536:Enzyme Activators; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008031:Lignin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D013552:Swine; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D020536:Enzyme Activators; D008031:Lignin; D000516:alpha-Amylases
keywords: Activator; Interaction; Lignin; α-Amylase