Functions
| Property | Value | Category |
|---|---|---|
| residues | 162 residues | Analytical Properties |
| oligomeric state | predominantly dimeric in physiological conditions; dissociates to monomer below pH 3; also occurs as tetrameric, octameric and other multimeric forms | Analytical Properties |
| amino acid residues | 162 amino acid residues, 162 | Analytical Properties |
| structure classification | lipocalin family | Analytical Properties |
| binding pocket ligands | cholesterol and vitamin D2 bound to central binding cavity at pH 7.3 (structures reported at resolutions 2.0 Å and 2.4 Å respectively; R = 0.221; Rfree = 0.295 for cholesterol; R = 0.212; Rfree = 0.297 for vitamin D2; not all ligand densities fully visible) | Analytical Properties |
| structure | globular protein of the lipocalin family; eight-stranded antiparallel β-barrel with a calyx; contains seven major strands of beta pleated sheet; small section of alpha helix | Analytical Properties |
| disulfide bonds | two internal disulfide bridges; a single sulfhydryl group at Cys121 | Analytical Properties |
| free sulfhydryl group | Cys121 buried in the protein; exposed under heating or disruption leads to disulfide exchange | Analytical Properties |
| oligomeric state at neutral pH | non-covalently linked dimer (at neutral pH) | Analytical Properties |
| Assay | ≥85% (PAGE) | Analytical Properties |