Description |
The Insulin-like Growth factors (IGFs) are mitogenic polypeptide growth factors that stimulate the proliferation and survival of various cell types including muscle, bone, and cartilage tissue, in vitro . The liver predominantly produces IGFs, although a variety of tissues produce IGFs at distinctive times. IGFs belong to the Insulin gene family, which also contains insulin and relaxin. The IGFs are similar by structure and function to insulin, but have a much higher growth-promoting activity than insulin. IGF-II expression is influenced by placenta lactogen, while IGF-I expression is regulated by growth hormone. Both IGF-I and IGF-II signal through the tyrosine kinase type I receptor (IGF-IR), but, IGF-II can also signal through the IGF-II/Mannose-6-phosphate receptor. Proteolytic processing of inactive precursor proteins, which contain N-terminal and C-terminal propeptide regions, generates mature IGFs. Recombinant human IGF-I and IGF-II are globular proteins containing 70 and 67 amino acids, respectively, and 3 intra-molecular disulfide bonds. Recombinant Human Insulin-like Growth Factor 1 is a single non-glycosylated polypeptide chain containing 70 amino acids. |
Storage and Stability |
The lyophilized protein is stable at 2-8C. Upon receipt, store desiccated at -20C. After reconstitution, the preparation is stable for up to one week at 2-8C. For maximal stability, apportion the reconstituted preparation into working aliquots and store at -20C to -80C. For long term storage of reconstituted protein, it is recommended that a carrier protein such as 0.1% BSA or HSA be added. This depends on the particular application. Avoid repeated freeze/thaw cycles. |