| Synonyms | Somatomedin C, IGF-I, IGFI, IGF1, IGF-IA, Mechano growth factor, MGF. |
| Introduction | The somatomedins, or insulin-like growth factors （IGFs）, comprise a family of peptides that play important roles in mammalian growth and development. IGF1 mediates many of the growth-promoting effects of growth hormone （GH; MIM 139250）. Early studies showed that growth hormone did not directly stimulate the incorporation of sulfate into cartilage, but rather acted through a serum factor, termed 'sulfation factor,' which later became known as 'somatomedin' （Daughaday et al., 1972）. Three main somatomedins have been characterized: somatomedin C （IGF1）, somatomedin A （IGF2; MIM 147470）, and somatomedin B （MIM 193190） （Rotwein, 1986; Rosenfeld, 2003）. |
| Description | Insulin-like Growth Factor-I Human Recombinant produced in E.Coli is a single, non-glycosylated, polypeptide chain containing 70 amino acids and having a molecular mass of 7655 Dalton.
IGF-I is purified by proprietary chromatographic techniques. |
| Source | Escherichia Coli. |
| Physical Appearance | Sterile Filtered White lyophilized （freeze-dried） powder. |
| Formulation | The protein was lyophilized with no additives. |
| Solubility | It is recommended to reconstitute the lyophilized IGF-1 in sterile 18MΩ-cm H2O not less than 100μg/ml, which can then be further diluted to other aqueous solutions. |
| Stability | Lyophilized Insulin-like Growth Factor-1 although stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution IGF1 should be stored at 4°C between 2-7 days and for future use below -18°C.
For long term storage it is recommended to add a carrier protein （0.1% HSA or BSA）.
Please prevent freeze-thaw cycles. |
| Purity | Greater than 95.0% as determined by（a） Analysis by RP-HPLC.
（b） Analysis by SDS-PAGE. |
| Amino acid sequence | The sequence of the first five N-terminal amino acids was determined and was found to be Gly-Pro-Glu-Thr-Leu. N-terminal methionine has been compley removed enzymatically. |
| Biological Activity | The ED50, calculated by the dose-dependant proliferation of murine BALB\C 3T3 cells （measured by 3H-thymidine uptake） is < 1.0 ng/ml, corresponding to a specific activity of 1x1,000,000 U/mg. For most in-vitro applications, IGF-I exerts its biological activity in the concentration range of 0.2-20 ng/ml. |
| Protein content | Protein quantitation was carried out by two independent methods
1. UV spectroscopy at 280 nm using the absorbency value of 0.502 as the extinction coefficient for a 0.1% （1mg/ml） solution. This value is calculated by the PC GENE computer analysis program of protein sequences （InliGenetics）.
2. Analysis by RP-HPLC, using a calibrated solution of IGF1 as a Reference Standard. |
| Usage | ProSpec's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals. |
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