Technical Data
Milk Fat Globule-EGF Factor 8, Recombinant, Human (MFG-E8, MFGM, Sperm Surface Protein SP47, MP47, Lactadherin)
Molecular Biology Storage: -20CShipping: Blue Ice
Human MFG-E8 (milk fat globule-EGF factor 8; also lactadherin, breast epithelial antigen BA46, and medin) is a 46kD, secreted, monomeric glycoprotein that is associated with the human milk fat globule (HMFG) membrane (1-3). It is expressed by mammary epithelial cell surfaces, artery media, and in several carcinomas (1-4). Human MGF-E8 is synthesized as a 387 amino acid (aa) precursor that contains a 23 aa signal sequence and a 364 aa mature region (SwissProt # Q08431). The mature molecule contains four N-linked glycosylation sites, an amino-terminal EGF-like domain, plus C1 and C2 Ig-like domains which are related to discoidin I and homologous to those of human coagulation factors V and VIII (2, 3). Within the EGF-like domain is an Arg-Gly-Asp (RGD) sequence, which is strategically placed in a hairpin loop between two antiparallel beta strands (2, 3). In this way, the EGF-like domain serves as a scaffold for the RGD sequence, which is proposed to promote cell adhesion by binding cell-surface integrin receptors, such as avb3 (2, 3). Human MFG-E8 shares 59%, 58%, 56%, and 52% aa sequence identity with porcine, bovine, rat, and mouse MFG-E8, respectively. Functionally, MFG-E8 in milk is reported to block rotavirus infection (5). MFG-E8 expression by macrophages promotes the phagocytosis of apoptotic thymocytes by forming a bridge between phosphatidylserine on apoptotic cells, and avb3 integrin on phagocytes (4, 6). The MFG-E8 expression by macrophages controls the accumulation of apoptotic membrane fragments in atherosclerotic plaques and substantially limits lesion development (4).

Calculated molecular mass of ~ 41.6kD. As a result of glycosylation, the recombinant protein migrates as an ~ 45-50kD protein in SDS-PAGE under reducing conditions.

Biological Activity:
Measured by the ability of the immobilized protein to support the adhesion of SVEC4-10 mouse vascular endothelial cells. When 5x10e4 cells/well are added to rhMFG-E8 coated plates (10ug/ml, 100ul/well), ~45-75% adhered after 60 minutes at 37C.

Storage and Stability:
Lyophilized powder may be stored at -20C. Stable for 12 months at -20C. Reconstitute by adding sterile PBS. Aliquot and store at -20C. Stable for 6 months at -20C. 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.

Molecular Weight:
Source: Recombinant corresponding to aa24-387 of human Milk Fat Globule-EGF Factor 8 with a C-terminal 6-His tag expressed in NSO cells.
Purity: 90%, as determined by SDS-PAGE under reducing conditions and visualized by silver stain. Endotoxin: <1EU/ug (LAL)
Form: Supplied as a lyophilized powder from PBS. Reconstitute with sterile PBS to a concentration of 0.1mg/ml.

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.
1. Larocca, D. et al., (1991) Cancer Res. 51:4994. 2. Cuoto, J.R. et al., (1996) DNA Cell Biol. 15:281. 3. Taylor, M.R. et al., (1997) DNA Cell Biol. 16:861. 4. Ait-Oufella, H. et al., (2007) Circulation 115:2168. 5. Newburg, D.S. et al., (1998) Lancet 351:1160. 6. Hanayama, R. et al., (2002) Nature 417:182.

Intended for research use only. Not for use in human, therapeutic, or diagnostic applications.