Epidermal Growth Factor, Pro-, Recombinant, Mouse (Pro-EGF, EGF)

EGF is the prototypic member of a family of growth factors that also includes amphiregulin, betacellulin, epigen, epiregulin, HB-EGF, neuregulins-1 through -6, and TGF-alpha (1). These proteins contain EGF-like domains with three intramolecular disulfide bonds between conserved cysteines (2). EGF family members are synthesized as transmembrane preproproteins with varying numbers of EGF-like domains (3). The extracellular region of mouse pro-EGF contains eight LDL R class B repeats and nine EGF-like domains (4). Mature EGF is derived from the juxtamembrane EGF-like domain. EGF binds ErbB1 and induces the formation of homodimers or heterodimers containing ErbB2 (5). pro-EGF is most highly expressed in the submaxillary gland and kidney (6). In the kidney, the 190 kD preproprotein is cleaved by membrane-associated serine proteases, liberating the extracellular region which is subsequently processed into smaller fragments including the 6 kD mature EGF (7-10). The various cleavage products produced in the kidney also are present in urine (9-11). In the submaxillary gland, however, nearly all EGF is processed intracellularly and stored in secretory vesicles (6, 12). The soluble precursor binds ErbB1 and induces cellular proliferation, although it is significantly less potent than mature EGF (8, 9). In human thyroid carcinoma cells, a splice variant of pro-EGF with a deletion in the cytoplasmic domain induces increased proliferative activity relative to wild type pro-EGF (13). Within the extracellular region, mouse pro-EGF shares 79% aa sequence identity with rat pro-EGF and 67%-69% with human, canine, feline, and porcine pro-EGF. Source: Mouse EGF (Met 1-Arg 1029), HHHHHH, A DNA sequence encoding the extracellular domain of mouse EGF sequence (Met 1-Arg 1029, Accession # P01132) (Gray, A., et al., 1983, Nature 303(5919):722) was fused with a 6X histidine tag at the C-terminus and expressed in a mouse myeloma cell line, NS0. , Molecular Mass: Based on the N-terminal sequencing, the recombinant mouse pro-EGF, generated by removal of its signal peptide, starts at Trp 29 and has a predicted molecular mass of 110 kD. As a result of glycosylation the recombinant mouse EGF migrates as a 160 kD protein in SDS-PAGE under reducing conditions. Endotoxin Level: < 1.0 EU per 1 µg of the growth factor as determined by the LAL method. , Activity: Measured by its ability to stimulate proliferation of Balb/3T3, a mouse fibroblast cell line. The ED50 for this effect is typically 1-5 ng/mL in a fluorometric assay using the redox sensitive dye, Resazurin. Reconstitution: It is recommended that sterile PBS containing at least 0.1% human serum albumin or bovine serum albumin be added to the vial to prepare a stock solution of no less than 10ug/ml. , Storage and Stability: Lyophilized samples are stable for up to twelve months at -20°C. Upon reconstitution, this protein can be stored under sterile conditions at 2°-8° C for one month or at -20°C in a manual defrost freezer for three months without detectable loss of activity. Avoid repeated freeze-thaw cycles.