Chick intestinal cytosol binding protein for 1,25-dihydroxyvitamin D/sub 3/: a study of analog binding

Journal Article · Sat Jan 01 04:00:00 EST 1977 · Arch. Biochem. Biophys.; (United States)

DOI:https://doi.org/10.1016/0003-9861(77)90134-5· OSTI ID:7208234

Kream, B E; Jose, M J.L.; DeLuca, H F

The structural features of 1,25-dihydroxyvitamin D/sub 3/ that permit its high affinity binding to a 3.7 S protein from chick intestinal cytosol were determined in a series of binding and competition experiments analyzed by sucrose density gradient centrifugation. Optimal binding to the 3.7 S protein was achieved when both 1..cap alpha..- and 25-hydroxyls were present in the vitamin D/sub 3/ molecule. Modification of the side chain by the introduction of a methyl on C-24 and a double bond on C-22,23 (1,25-dihydroxyvitamin D/sub 2/) did not alter the binding of 1,25-dihydroxyvitamin D/sub 3/, but significantly diminished the binding of 25-hydroxyvitamin D/sub 3/. However, introduction of a hydroxyl on C-24 decreased the ability of either 1,25-dihydroxyvitamin D/sub 3/ or 25-hydroxyvitamin D/sub 3/ to compete, especially when the 24-hydroxyl was in the S configuration. These results reveal that the 3.7 S protein requires specific ligand structural features for binding and suggest that metabolite discrimination by the chick intestinal receptor system is likely located in the 3.7 S cytosol protein.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 7208234
• Journal Information: Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 179; ISSN ABBIA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550500 -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOCHEMISTRY
BIRDS
BODY
CENTRIFUGATION
CHEMICAL BONDS
CHEMICAL REACTIONS
CHEMISTRY
CHICKENS
CHOLECALCIFEROL
DIGESTIVE SYSTEM
FOWL
GASTROINTESTINAL TRACT
INTESTINES
LIGANDS
METABOLISM
MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
ORGANS
PROTEINS
SEPARATION PROCESSES
ULTRACENTRIFUGATION
VERTEBRATES
VITAMIN D
VITAMINS