Some characteristics of cytosol binding protein for 1 alpha,25-dihydroxycholecalciferol, 24R,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol in rat parotid gland.
1. 1 alpha,25-dihydroxycholecalciferol (1,25-(OH)2VD3), 24R,25-dihydroxycholecalciferol (24,25-(OH)2VD3) and 25-hydroxycholecalciferol (25-OHVD3) binding proteins were existed in cytosol of rat parotid gland. 2. The dissociation constants of binding proteins for 1,25-(OH)2VD3, 24,25-(OH)2VD3 and 25-OHVD3 were 3.15 x 10(-9), 5.05 x 10(-9) and 6.60 x 10(9) M, respectively. 3. The mol wt and the isoelectric point (pI) of binding proteins for 1,25-(OH)2VD3, 24,25-(OH)2VD3, 24,25-(OH)2VD3 and 25-OHVD3 were the same to each other (with mol wt of 155,000 and pI of 4.87). 4. The binding specificity of 1,25-(OH)2VD3 binding protein was similar to that of 24,25-(OH)2VD3 and 25-OHVD3 binding protein. 5. The extent of loss of binding activity for 1,25-(OH)2VD3 by pronase and trypsin was much greater than that of binding activity for 24,25-(OH)2VD3 and 25-OHVD3.
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006887:Hydroxycholecalciferols / Q000378:metabolism*; D007526:Isoelectric Point; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D010306:Parotid Gland / Q000378:metabolism*; D051381:Rats; D011987:Receptors, Steroid / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013696:Temperature
D002352:Carrier Proteins; D006887:Hydroxycholecalciferols; D011987:Receptors, Steroid; D013439:Sulfhydryl Reagents