Formation and characterisitcs of hepatic dexamethasone-receptor complexes of different molecular weight

摘要: Abstract The dexamethasone-binding receptor protein in rat liver cytosol has a Stokes radius of 61 A and sedimentation coefficient 4.0 S. In contrast, cell nuclei labelled with [ 3 H]dexamethasone vivo or vitro (reconstitution experiments H]dexamethasone-labelled isolated unlabelled nuclei) contain high-salt-extractable dexamethasone-receptor complex 30–36 3.2 Exposure homogenate 1000 × g supernatant to low ionic strenght during preparation resulted conversion the 36 very similar intranuclear form dexamethasone receptor. → complex-verting activity was present both 100 −10 000 sediment homogenate, from which it could be extracted by hypotonic media, nuclei, hypertonic media. Mild digestion trypsin also gave rise A. Reconstitution indicated that complexes were taken up nuclei; reextraction incubated revealed this had been converted complex. Further teh H]dexamethasone-receptor extract formation third 19 2.5 approximate molecular weights 61, calculated as 102 000, 46 00 respectively, frictional ratios molecules 1. 84, 38 amd 1.00, respectively. It is concluded nuclear formed proteolytic latter contains at least two sites relatively high sensitivity protelytic cleavage.