The ED50 was determined by the dose - dependent stimulation of the proliferation of human MCF - 7 cells is < 0.5 ng/mL, corresponding to a specific activity of > 2 x 106 units/mg.
纯度
< 98 % by SDS-PAGE gel and HPLC analyses.
内毒素水平
Endotoxin level is less than 0.1 ng per μg (1 EU/μg).
限制
仅限研究用
状态
Lyophilized
注意事项
As with any protein, exposing Heregulin-B1 recombinant protein to repeated freeze / thaw cycles is not recommended. When working with proteins care should be taken to keep recombinant protein at a cool and stable temperature.
储存条件
-20 °C
储存方法
The recombinant protein is stable for at least 2 years from date of receipt at -20 °C. Reconstituted Heregulin-B1 is stable for at least 3 months when stored in working aliquots with a carrier protein at -20 °C.
Neuregulin/Heregulin is a family of structurally related polypeptide growth factors derived from alternatively spliced genes (NRG1, NRG2, NRG3 and NRG4). To date, there are over 14 soluble and transmembrane proteins derived from the NRG1 gene. Proteolytic processing of the extracellular domain of the transmembrane NRG1 isoforms release soluble growth factors. HRG1-beta1 contains an Ig domain and an EGF-like domain that is necessary for direct binding to receptor tyrosine kinases erb3 and erb4. This binding induces erb3 and erb4 heterodimerization with erb2, stimulating intrinsic kinase activity, which leads to tyrosine phosphorylation. Although HRG1-beta1 biological effects is still unclear, it has been found to promote motility and invasiveness of breast cancer cells which may also involve up-regulation of expression and function of the autocrine motility-promoting factor (AMF). Recombinant human Heregulin-beta1 (HRG1-beta1) is a 7.5 kDa polypeptide consisting of only the EGF domain of heregulin-beta1 (65 amino acid residues).