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	Spectral Analysis of Polyphenol Oxidase (PPO) and Lipoxygenase (LOX) Treated by Pulsed Electric Field
	Luo Wei ; zhang Ruo-bing ; Chen Jie ; Wang Li-ming ; Guan Zhi-cheng ; Jia Zhi-dong
	2010-10-12 ; 2010-10-12
关键词	Pulsed electric field Polyhenol oxidase Lipoxygenase Circular dichroism spectra Fluorescence spectra INACTIVATION MICROORGANISMS PROTEIN FOODS Spectroscopy
中文摘要	Inactivation effect of pulsed electric field WED on polyphenol oxidase (PPO) and lipoxygenase (LOX) was investigated using a laboratory PEF system with a coaxial treatment chamber. Circular dichroism (CD) and fluorescence analysis were used to study the conformation change of the protein. The experimental results show that PPO and LOX can be effectively inactivated by the PEF treatment. Inactivation effect of PPO and LOX increases with the increase in the applied electric strength and the treatment time. Activity of PPO and LOX can be reduced by 60. 3% and 21. 7% at 20 kV . cm(-1) after being treated for 320 mu s respectively. The decrease of the negative peaks (208 and 215 nm in PPO spectra, 208 nm and 218 nm in LOX spectra) in CD spectra of PPO and LOX shows that PEF treatment caused a loss of alpha-helix and increase in beta-sheet content, indicating, that conformation changes occur in the secondary structure of PPO and LOX enzyme. This effect was strengthened as the applied electric field increased: alpha-helical content of PPO and LOX was 56% and 29% after being treated at 8 kV . cm(-1), however, when the electric field was increased up to 20 kV . cm(-1) alpha-helical content of PPO and LOX decreased to 21% and 16% respectively. The decrease rate of alpha-helix and increase rate of beta-sheet in PPO are higher than LOX, indicating that the second conformation of PPO is less resistant to PEF treatment than LOX. The fluorescence intensity of LOX increases after PEF treatment. At the same time, increasing the applied pulsed electric field increases the fluorescence intensity emitted. Fluorescence measurements confirm that tertiary conformation changes occur in the local structure of LOX. However the possible mechanism of the conformation change induced by the PEF treatment is beyond the scope of the present investigation.
语种	中文 ; 中文
出版者	OFFICE SPECTROSCOPY & SPECTRAL ANALYSIS ; BEIJING ; NO 76 COLLAGE SOUTH RD BEIJING, BEIJING 100081, PEOPLES R CHINA
内容类型	期刊论文
源URL	[http://hdl.handle.net/123456789/81742]
专题	清华大学
推荐引用方式 GB/T 7714	Luo Wei,zhang Ruo-bing,Chen Jie,et al. Spectral Analysis of Polyphenol Oxidase (PPO) and Lipoxygenase (LOX) Treated by Pulsed Electric Field[J],2010, 2010.
APA	Luo Wei,zhang Ruo-bing,Chen Jie,Wang Li-ming,Guan Zhi-cheng,&Jia Zhi-dong.(2010).Spectral Analysis of Polyphenol Oxidase (PPO) and Lipoxygenase (LOX) Treated by Pulsed Electric Field..
MLA	Luo Wei,et al."Spectral Analysis of Polyphenol Oxidase (PPO) and Lipoxygenase (LOX) Treated by Pulsed Electric Field".(2010).

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