Conformational changes of the alpha 1-proteinase inhibitor affecting its cholesterol binding ability.
The effect of conformational changes of the alpha 1-proteinase inhibitor (alpha 1PI) on alpha 1PI-cholesterol complex (1:2 mol/mol) formation in vitro was studied with electrophoretic and gel chromatographic methods. Native alpha 1PI was modified by adding free thiol agents such as glutathione, cysteine HCl, or DL-homocysteine, by heating, or by cleavage with pancreatic elastase or trypsin. Conformational changes of the alpha 1PI molecule induced by these procedures were all accompanied by a loss of its ability to bind cholesterol in vitro under standard experimental conditions. The data suggest alpha 1PI-cholesterol binding to be affected by both direct and indirect modifications of the alpha 1PI-reactive center, that is situated on a mobile peptide loop.
Department of Medicine, University of Lund, Malmö General Hospital, Sweden.
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Janciauskiene
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Eriksson
D002784:Cholesterol / Q000378:metabolism*; D002850:Chromatography, Gel; D004220:Disulfides; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D011487:Protein Conformation; D013816:Thermodynamics; D000515:alpha 1-Antitrypsin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
D004220:Disulfides; D000515:alpha 1-Antitrypsin; D002784:Cholesterol