长白山白眉蝮蛇蛇毒磷脂酶A_2的荧光光谱

Fluorescence Analysis of Phospholipase A2 Isolated from Chinese Agkistrodon Blomhoffii Ussurensis Venom

利用荧光光谱系统研究了长白山白眉蝮蛇蛇毒磷脂酶Ａ_２的荧光特性。研究结果表明：当发射波长与激发波长差为２０ｎｍ和７５ｎｍ时，ＰＬＡ２的同步荧光分别主要由酪氨酸（Ｔｙｒ）残基和色氨酸（Ｔｒｐ）残基所贡献。缓冲溶液的酸度变化能够明显影响ＰＬＡ２氨基酸侧链的电荷分布，从而改变 ＰＬＡ２的荧光发射强度。金属离子Ｃａ２＋一方面能增强ＰＬＡ２的荧光强度，另一方面也能够加快ＰＬＡ２与底物二棕榈酸磷脂酰胆碱（ＤＰＰＣ）的反应速度。

The general and synchronous spectra of phospholipase A2 (PLA2 ) isolated from Chinese agkistrodon blomhoffii Ussurensis snake venom were studied. The chromophores of PLA2 were mainly contributed by tyrosine and trypophane residues when the intervals between the excitation wavelength and the emssion waveleagth (△λ ) were 20nm and 75nm, respectively. The pH of buffers could change the fluorescence intensities of PLA2 by changing the charge distribution of its amino acid chain. Ca2+ can not only increase the emission fluorescence intensity of PLA2 but also improve the reaction rate of PLA2 with its corresponding substrate DPPC.