title: Comparison of pyridoxal phosphate and 0.4 M KCl-extracted nuclear glucocorticoid receptors in HeLa S3 cells.
abstract: A comparison of the physicochemical properties between pyridoxal 5'-phosphate- and 0.4 M KCl-extracted nuclear glucocorticoid receptors has been made utilizing HeLa S3 cells as a source of receptor. Both pyridoxal 5'-phosphate/NaBH4-reduced and 0.4 M KCl-extracted receptors sedimented as approximately 3.5-4.5 S species in 5-20% sucrose gradients containing 0, 0.15, and 0.4 M KCl. Under low-ionic-strength buffer conditions, pyridoxal 5'-phosphate-extracted receptor elutes close to the void volume of a Sephacryl S-300 gel-exclusion column. Increasing the [KCl] of the column to 0.4 M resulted in the elution of receptor with a Stokes radius of 58 A and calculated Mr = 96,000. Nuclear receptors extracted with 0.4 M KCl also formed a large-molecular-weight complex which eluted close to the void volume of the gel-exclusion column. Increasing the [KCl] to 0.4 M had the effect of shifting this receptor form to a species which had a Stokes radius of 62 A and calculated Mr = 89,700. Ion-exchange analysis of nuclear-extracted receptors revealed that 0.4 M KCl-extracted receptors exhibited considerable charge heterogeneity, whereas pyridoxal 5'-phosphate-extracted receptors did not. Pyridoxal 5'-phosphate-extracted receptors (approximately 86%) eluted from DEAE-cellulose at a [KCl] greater than 0.15 M; approximately 14% of the receptors had little affinity for DEAE-cellulose. Pyridoxal phosphate-treated receptors had little affinity for hydroxylapatite, phosphocellulose, and DNA-cellulose. The predominant form of 0.4 M KCl-extracted nuclear receptors (approximately 78%) eluted from DEAE-cellulose between 0.05 and 0.15 M KCl, a position coincident with "activated" glucocorticoid receptors. The remaining receptor fraction (approximately 22%) eluted from DEAE-cellulose at a [KCl] greater than 0.15 M, a position coincident with "unactivated" glucocorticoid receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
mesh_terms: D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009994:Osmolar Concentration; D011189:Potassium Chloride / Q000494:pharmacology*; D011732:Pyridoxal Phosphate / Q000494:pharmacology*; D011965:Receptors, Glucocorticoid / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D011987:Receptors, Steroid / Q000378:metabolism*; D014222:Triamcinolone Acetonide / Q000378:metabolism
chemical_list: D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D011732:Pyridoxal Phosphate; D011189:Potassium Chloride; D014222:Triamcinolone Acetonide