Synthesis of 25-hydroxyvitamin D3 3 beta-3'-[N-(4-azido-2-nitrophenyl)amino]propyl ether, a second-generation photoaffinity analogue of 25-hydroxyvitamin D3: photoaffinity labeling of rat serum vitamin D binding protein

Biochemistry. 1991 May 14;30(19):4809-13. doi: 10.1021/bi00233a024.

Abstract

Vulnerability of 25-hydroxy-[26,27-3H]vitamin D3 3 beta-N-(4-azido-2-nitrophenyl)glycinate, a photoaffinity analogue of 25-hydroxyvitamin D3 (25-OH-D3) (Ray et al., 1986) toward standard conditions of carboxymethylation promoted us to synthesize 25-hydroxyvitamin D3 3 beta-3'-[N-(4-azido-2-nitrophenyl)amino]propyl ether (25-ANE), a hydrolytically stable photoaffinity analogue of 25-OH-D3, and 25-hydroxyvitamin D3 3 beta-3'-[N-(4-azido-2-nitro-[3,5-3H]phenyl)amino] propyl ether (3H-25-ANE), the radiolabeled counterpart of 25-ANE. Competitive binding assays of 25-OH-D3 and 25-ANE with rat serum demonstrated that 25-ANE competes for the 25-OH-D3 binding site in rat serum vitamin D binding protein (rDBP). On the other hand, UV exposure of a sample of purified rat DBP (rDBP), preincubated in the dark with 3H-25-ANE, covalently labeled the protein. However, very little covalent labeling was observed in the absence of UV light or in the presence of a large excess of 25-OH-D3. These results provide strong evidence for the covalent labeling of the 25-OH-D3 binding site in rDBP by 3H-25-ANE.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Affinity Labels
  • Animals
  • Autoradiography
  • Azides / chemical synthesis*
  • Binding, Competitive
  • Calcifediol / analogs & derivatives*
  • Calcifediol / chemical synthesis
  • Calcifediol / chemistry*
  • Electrophoresis, Polyacrylamide Gel
  • Photochemistry
  • Rats
  • Ultraviolet Rays
  • Vitamin D-Binding Protein / chemistry*

Substances

  • Affinity Labels
  • Azides
  • Vitamin D-Binding Protein
  • 25-hydroxyvitamin D3 3'-(N-(4-azido-2-nitrophenyl)amino)propyl ether
  • Calcifediol