Lipopolysaccharide Binding Protein, aa26-481, Recombinant, Human, Histidine-tagged (LBP, LPSBP)

LBP (Lipopolysaccharide binding protein) is a 58-62kD, glycoprotein member of the BPI/LBP family of lipid-binding proteins (1-4). It is secreted by hepatocytes, gingival keratinocytes, intestinal paneth cells, type II Greater alveolar cells, lacrimal and submandibular gland epithelium, and caudal epididymal epithelium (5-10). LBP is a class 1 APR (acute phase reactant) that is induced upon exposure to both IL-1 and IL-6 (11). Following its synthesis and release, LBP interacts with bacterial wall components, lipopolysaccharide/LPS/Lipid A from Gram- (Gm-) bacteria, and lipoteichoic acid/LTA from Gm+ bacteria (12-16). In the case of LPS, this interaction occurs both in the bacterial cell wall, and within the intercellular space, where LPS micelles naturally form following bacterial death and cell wall dissolution (17-20). LBP induces disassembly of LPS micelles, allowing for LPS binding to LBP, and a heparin-mediated transfer of LPS from LBP to membrane-bound CD14 on the surface of monocytes/macrophages (18, 21). This CD14/LPS complex activates a TLR4/MD2 membrane complex, resulting in the production of NO and TNFa (22). TNFa serves as a chemoattractant for PMNs, and an initiator of coagulation that helps to wall-off and localize microbial elements (19). In addition to the above, LBP is also reported to transfer LPS to lipoproteins, particularly HDL and LDL (22-25). For LDL, this transfer inhibits monocyte activation; for HDL, the effect may be either stimulatory or inhibitory, depending upon the circumstances (22). Human LBP is synthesized as a 481aa precursor that contains a 25aa signal sequence and a 456aa mature region (aa26-481) (26). It contains an N-terminal LPS binding region (aa29-252) plus a likely C-terminal LPS transfer region (aa276-477) (26, 27). There are two potential splice variants. One shows a four aa substitution for aa154-157 coupled to an Ala substitution for aa266-270, while another contains a seven aa substitution for aa468-481. Mature human LBP shares 68%, 69% aa identity with mouse and rat LBP, respectively (14, 22).\n\nSource: \nRecombinant corresponding to aa26-481 from human LBP, fused with 6-His tag at C-terminal, expressed in myeloma cell line, NSO cells.\n\nMolecular Weight: \n~51.7kD\n\nEndotoxin Level:\n(same/less than)1EU/1ug (LAL)\n\nBiological Activity:\nMeasured by its ability to enhance LPS-stimulated IL-8 secretion by THP-1 human acute monocytic leukemia cells. The ED50 for this effect is typically 0.25-1.5ng/mL.\n\nStorage and Stability:\nLyophilized powder may be stored at -20 degrees C. Stable for 12 months at -20 degrees C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Reconstituted product is stable for 6 months at -20 degrees 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.

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SPECIFICATIONS

Catalog Number

L2525-30B

Size

25ug

Form

Supplied as a lyophilized powder in PBS. Reconstitute with PBS to 100ug/ml.

Purity

~95% (SDS-PAGE)

References

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