TOPO-DYNAMIC CHARACTERISTICS OF HUMAN-PLASMA VLDL APOLIPOPROTEINS AND EFFICIENCY OF TRIACYLGLYCEROL HYDROLYSIS BY LIPOPROTEIN-LIPASE

作     者：DERGUNOV, AD SHUVAEV, VV PEROVA, NV 

作者机构：MOSCOW PREVENT MED RES CTR DEPT BIOCHEM 10 PETROVERIGSKI ST MOSCOW 101953 USSR 

出 版 物：《BIOCHIMICA ET BIOPHYSICA ACTA》 (Biochim. Biophys. Acta Lipids Lipid Metab.)

年 卷 期：1989年第1005卷第1期

页      面：79-86页

核心收录：

主　　题：Lipid hydrolysis VLDL Apolipoprotein topography (Human plasma) VLDL very-low-density lipoproteins LDL low-density lipoproteins HDL high-density lipoproteins LPL lipoprotein lipase apoA B, E, C, apolipoproteins of VLDL (apo B, E and C) LDL (apoB) HDL (apoA, E and C) K SV Stern-Volmer quenching constant f chromophore accessibility for quencher molecules K m app apparent Michaelis constant V max app apparent maximal reaction velocity SDS sodium dodecyl sulfate 

摘      要：A lower accessibility to water-soluble quenchers of tryptophanyls of VLDL apolipoproteins B, E, C, as compared to LDL apoB chromophores has been detected by a fluorescence quenching technique. The dynamic behavior of the tryptophanyls of VLDL amphipathic apolipoproteins E and C did not change in the presence of a detergent, Tween-20, at sub-lytic concentrations. However, a reversible structural transition registered by the red shift of the emission spectrum maximum and the changes in the quenching pattern by I- occurred under these conditions. The increase in the VLDL tryptophanyl accessibility to acrylamide and the decrease in the quenching constant were observed at partial and complete solubilization of the VLDL particles by the detergent. Dissociation of apolipoproteins from VLDL occurred after their treatment with Tween-20 or lipoprotein lipase isolated from bovine milk, and the tryptophanyl population not participating in fluorescence energy transfer on lipid phase-localized fluorescent probe pyrene appeared. In the presence of Tween-20, the relative affinity of apoE for the lipid matrix of VLDL was lower than that of apoC. Besides, the uncompetitive mode of inhibition of the LPL activity by apoC-III has been demonstrated. It is suggested that: (1) the amphipathic apolipoproteins E and C are organized as clusters on the VLDL surface and/or partially shielded by apolipoprotein B;(2) self-regulation of lypolysis may exist involving detergent-like reaction product accumulation and changes in relative apolipoprotein contents.