title: Aggregation and conformational change of mushroom (Agaricus bisporus) polyphenoloxidase subjected to thermal treatment.
abstract: This study investigated changes in the activity, conformation and microstructure of mushroom polyphenoloxidase (PPO) subjected to thermal treatment. The inactivation of PPO can be achieved by high temperature-short time or mild temperature-long time treatment. Circular dichroism and fluorescence spectra suggested that heating process induced the rearrangement of secondary structure and the disruption of tertiary structure. Red shifts of fluorescence spectra showed positive correlations with the inactivation rate of PPO. There were significant differences in the conformation and molecular microstructure among PPO samples with the same relative activity, which were obtained by treating PPO at 45, 55 and 65°C for different times. In summary, PPO molecules were deformed at mild temperature, while higher temperature induced the formation of large aggregates. PPO with the same relative activity might exist in different forms.
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors: Lei
authors: L
authors: Zhou
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China. Electronic address: liuwei@ncu.edu.cn.
authors: Wei
authors: W
authors: Liu
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors: Liqiang
authors: L
authors: Zou
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors: Zhiqiang
authors: Z
authors: Xiong
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors: Xiuting
authors: X
authors: Hu
authors: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
authors: Jun
authors: J
authors: Chen
mesh_terms: D000364:Agaricus / Q000737:chemistry* / Q000378:metabolism; D004156:Catechol Oxidase / Q000737:chemistry* / Q000378:metabolism; D002942:Circular Dichroism / Q000379:methods; D006358:Hot Temperature / Q000009:adverse effects*; D010936:Plant Extracts / Q000737:chemistry / Q000378:metabolism; D066329:Protein Aggregates / Q000502:physiology; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D014675:Vegetables / Q000737:chemistry / Q000378:metabolism
chemical_list: D010936:Plant Extracts; D066329:Protein Aggregates; D004156:Catechol Oxidase
keywords: Aggregation; Conformation; Inactivation; Microstructure; Polyphenoloxidase; Thermal treatment