Recombinant production and characterization of insulin-like growth factor binding proteins (IGFBP)

Diabetes is a genetic or nutritionally caused by the fact that the pancreatic gland does not produce enough insulin hormone or the insulin hormone it produces cannot be used effectively. As a result of this, it is a life-long disease caused by the development of abnormal differences in blood glucose level. Since diabetes is an increasing health problem, it is tried to develop alternative, effective, easy to use therapeutic treatment methods. Potential therapeutic applications of insulin-like growth factors (IGFs) are extensive. The IGF family has been used in the treatment of cancer, growth retardation, musculoskeletal diseases and neurodegenerative diseases, especially diabetes. IGFs are structurally similar to insulin and are present in the biological fluid bound to insulin-like growth factors-binding protein (IGFBP). Up to present, there are six mammalian IGFBPs characterized and named as IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, IGFBP-5, IGFBP-6. IGFBPs bind to IGFs higher affinity than Type-1 IGF receptors. Thus, they control their binding to their receptors and regulate IGFs activity. IGFBPs are extremely important proteins with IGF dependent and IGF independent effects In this study, optimization of IGFBP-3 recombinant production, which is more than 60% of circulating IGFBPs and considered to be the most important of IGFBP. Two different E.coli strains, E.coli BL21 and E.coli Shuffle T7 Express, were studied in two different pET expression systems, pET21a and pET22b, at different temperatures and different induction concentrations.