S100B, previously called S100beta, belongs to the S100 family within the EF-hand superfamily of Ca2+ binding proteins (1-3). S100 proteins contain two EF-hand motifs that differ in affinity, separated by a hinge region with a hydrophobic cleft that is exposed upon Ca2+ binding (4). S100B is a 91 amino acid (aa) protein, after removal of the initial methionine, and is found as homodimers of 10.4kD monomers. Human S100B shares 99%, 98%, 100%, 99% and 97% aa sequence identity with mouse, rat, rabbit, equine and bovine S100B, respectively. Within the S100 family, human S100B shows the highest aa identity (59%) with S100A1. S100B is expressed primarily by astrocytes and oligodendrocytes in the central nervous system, and by Schwann cells in the peripheral nervous system (5). Ca2+-bound S100B interacts in vitro with at least 20 cytoplasmic proteins, including several structural molecules such as tubulin and GFAP (1, 4). It can inhibit the phosphorylation of these kinase substrates and others such as tau and neuromodulin (1, 5).
Astrocytes can secrete S100B, which then acts in a cytokine-like manner (5, 6). Nanomolar concentrations of S100B are secreted constitutively, promote proliferation, and are neurotrophic and anti-apoptotic (1, 6). Blood levels of S100B reflect extracellular concentrations within the nervous system, and are elevated in Down’s syndrome, Alzheimer’s disease and Tourette’s syndrome, metabolic stress, acute brain injury and brain tumors (5, 7). Micromolar concentrations of S100B can be destructive and pro-apoptotic; they induce the expression of iNOS, COX-2, IL-1, IL-6 and TNF-alpha by microglia, astrocytes or neurons (6, 8-11). Most extracellular actions of S100B can be mediated by RAGE (receptor for advanced glycation end products), which is also a receptor for other S100 proteins (6, 10, 11).
Source:Recombinant protein corresponding to aa1-92, Met1-Glu92, from human S100B expressed in E. coli.
Molecular Weight:~7kD
Endotoxin:<0.10EU/1ug (LAL method).
Biological Activity:Measured in a cell proliferation assay using human peripheral blood monocytes. The ED50 for this effect is 1-4ug/mL.
Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
仕様
Size：50ug
Source Antigen：Recombinant, E. coli
Grade：Highly Purified
Purity：~95% (SDS-PAGE)
Form：Supplied as a lyophilized powder in PBS. Reconstitute with 250ul sterile PBS.
