Enhancement of Agkistrodon piscivorus piscivorus venom phospholipase A2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: studies with fluorescent probes of membrane structure.
Enhancement of Agkistrodon piscivorus piscivorus venom phospholipase A2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: studies with fluorescent probes of membrane structure.
复制标题
溶血卵磷脂和棕榈酸增强Agkistrodon piscivorus毒液磷脂酶A2对磷脂酰胆碱囊泡的活性：膜结构荧光探针的研究。
DOI：
10.1021/bi00024a003
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发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
Bell,JD
中科院分区：
文献类型：
--
作者：
Sheffield,MJ;Baker,BL;Li,D;Owen,NL;Baker,ML;Bell,JD
The activity of phospholipase A2 from snake venom to hydrolyze bilayers of phosphatidylcholines is greatly enhanced by the presence of the hydrolysis products, lysolecithin and fatty acid, in the bilayer. The fluorescence of several probes of membrane structure was used to monitor changes in bilayer physical properties during vesicle hydrolysis. These changes were compared to emission spectra and fluorescence polarization results occurring upon direct addition of lysolecithin and/or fatty acidto the bilayer. The excimer to monomer ratio of 1, 3-bis (1-pyrene) propane was insensitive to vesicle hydrolysis, suggesting that changes in the order of the phospholipid chains were not relevant to the effect of the hydrolysis products on phospholipase activity. The fluorescence of 6-propionyl-2-(dimethylamino)-naphthalene (Prodan) suggested that the polarity of the bilayer in the region of the phospholipid head groups increases as the hydrolysis products accumulate in the bilayer. The fluorescence of 6-dodecanoyl-2-(dimethylamino) naphthalene (Laurdan) confirmed thatsuch effects were restricted to the bilayer surface. Furthermore, the lysolecithin appeared to be the product most responsible for these changes. These results suggested that lysolecithin increases the activity of phospholipase A2 during vesicle hydrolysis by dismpting the bilayer surface, making the phospholipid molecules more accessible to the enzyme active site.Phospholipase A2 research is important because of increas-ing evidence of the enzyme’s role in transduction of hormone signals, membrane homeostasis, and the pathology of numer-ous inflammatory diseases (Jain & Berg, 1989; Kudo et al., 1993). Furthermore, studies using small soluble phospho-lipases A2 (PLA2) 1 from pancreatic juices and snake venoms (which are related structurally to the enzyme secreted by platelets and present in synovial fluid; Kudo et al., 1993; Dennis, 1994) with various types of phospholipid substrates have provided useful information pertinent to general understanding of lipid/protein interactions. An interesting feature shared by PLA2 and other lipases has been termed “interfacial activation”[reviewed in Verheij et al. 1981)]. Interfacial activation refers to the fact that PLA2 activity is muchhigher toward aggregated compared to monomeric substrate. A related phenomenon is the observation that PLA2 activity toward aggregated substrate also depends on the physical properties of the aggregate. For example, in the case of zwitterionic substrate, PLA2 activity is highest when the phospholipid is in micellar form (Verheij et al., 1981). If the phospholipid is organized into a bilayer, the PLA2 activity is influenced by the curvature of the
