Use of a novel rapid preparation of fat-cell plasma membranes employing Percoll to investigate the effects of insulin and adrenaline on membrane protein phosphorylation within intact fat-cells

作者：Graham J. Belsham, R M Denton, Michael J. A. Tanner · 发表于：Biochemical Journal · 年份：1980 · DOI：10.1042/bj1920457 · 被引用次数：175 · 研究领域：Lipid Membrane Structure and Behavior、Fatty Acid Research and Health、Diet, Metabolism, and Disease

1. A rapid method was developed for the preparation of plasma membranes from either isolated rat fat-cells or intact epididymal fat-pads with the use of density-gradient centrifugation in the presence of Percoll. On the basis of 5'-nucleotidase activity, the yield of plasma membranes was about 50% and purification over 10-fold. Activities of marker enzymes indicated that contamination by mitochondria and microsomal fraction was small. 2. Incorporation of 32Pi into proteins associated with plasma membranes within isolated fat-cells was investigated. Four major bands of labelled phosphoproteins were separated by sodium dodecyl sulphate/polyacrylamide-slab-gel electrophoresis; the apparent subunit mol.wts. were 67 000, 61 000, 26 000 and 20 000. None of these phosphoprotein bands corresponded to periodate/Schiff-staining glycoproteins. The extent of phosphorylation of the 61 000 mol.wt phosphoprotein band was increased by about 30 and 60% after exposure of fat-cells for 15 min to insulin or adrenaline respectively.