论文部分内容阅读
以荧光光度法研究了大鼠肝ＬＤＨ－Ｍ４与磷脂脂质体的相互作用。磷脂脂质体对ＬＤＨ－Ｍ４具有抑制作用。磷脂酰肌醇（ＰＩ）脂质体的作用比磷脂酰乙醇胺（ＰＥ）大。当磷脂／蛋白（Ｗ／Ｗ）比为６时，ＰＩ能完全抑制ＬＤＨ的活性，抑制作用呈剂量效应。而磷脂酰乙醇胺，当其磷脂／蛋白（Ｗ／Ｗ）比超过２时，抑制作用不明显，抑制作用呈非剂量效应。当以２８０ｎｍ为激发波长时，ＬＤＨ－Ｍ４的发射峰为３４５ｎｍ，主要为色氨酸的吸收。磷脂脂质体对ＬＤＨ－Ｍ４的内源性荧光具有猝灭作用，并使发射峰红移，ＰＩ的作用比ＰＥ的作用大，ＮａＣｌ能减轻磷脂脂质体对酶的内源性荧光的影响，该结果提示静电作用在磷脂与酶相互作用过程中是主要的。Ｓｔｅｒｎ－Ｖｅｌｍｅｒ图提示，荧光猝灭机制主要为静态猝灭，即酶吸附于磷脂脂质体表面形成了酶脂质体复合物。这种吸附改变了酶的构象，从而影响了酶的活性。
The interaction of rat liver LDH-M4 with phospholipid liposomes was studied by fluorimetry. Phospholipid liposomes have an inhibitory effect on LDH-M4. Phosphatidylinositol (PI) liposomes have a greater effect than phosphatidylethanolamine (PE). When the phospholipid / protein (W / W) ratio was 6, PI could completely inhibit the activity of LDH, and the inhibitory effect was dose-effect. Phosphatidylethanolamine, when its phospholipid / protein (W / W) ratio is more than 2, showed no obvious inhibitory effect and no inhibitory effect. When 280nm excitation wavelength, LDH-M4 emission peak 345nm, mainly the absorption of tryptophan. Phospholipid liposomes quench the endogenous fluorescence of LDH-M4 and red-shift the emission peak, and the effect of PI is greater than that of PE. NaCl can reduce the influence of phospholipid liposomes on the endogenous fluorescence of the enzyme This result suggests that the electrostatic interaction is dominant during the interaction of phospholipids and enzymes. Stern-Velmer plots suggest that the fluorescence quenching mechanism is mainly static quenching, that is, the enzyme is adsorbed on the surface of the phospholipid liposome to form the enzyme liposome complex. This adsorption changes the conformation of the enzyme and thus the enzyme’s activity.