The sequence of the first ten N-terminal amino acids was determined and was found to be Met-Ser-Pro-Glu-Thr-Leu-Cys-Gly-Ala-Glu.
Binding assays of the 125I-Gealthead Seabream IGF1 to Gilthead Seabream or carp (Cyprinus carpio) sera resulted in high specific binding, indicating the existence of one or more IGF-binding proteins. In binding experiments to crude Gilthead Seabream brain homogenate, using human (h) IGF-I as a ligand, the respective IC50 value of hIGF1 was about fourfold lower than that of Gilthead Seabream IGF-1. Recombinant Gilthead Seabream IGF-1 exhibited mitogenic activity in a mouse mammary gland-derived MME-L1 cell line which was approximately 200-fold lower than that of hIGF1. Binding experiments to intact MME-L1 cells suggests that this difference most likely results from a correspondingly lower affinity for IGF1 receptor in these cells. In contrast, the activities of Gilthead Seabream IGF-I and hIGF-I measured by 35S uptake by gill arches from the goldfish (Carassius auratus) were identical, indicating that the recombinant Gilthead Seabream IGF-I is biologically active.
The protein was lyophilized from a concentrated (1mg/ml) solution with 0.02% NaHCO3.
Sterile Filtered White lyophilized (freeze-dried) powder.
Somatomedin C quantitation was carried out by two independent methods:1. UV spectroscopy at 280 nm using the absorbency value of 0.60 as the extinction coefficient for a 0.1% (1mg/ml) solution at pH 8.0. This value is calculated by the PC GENE computer analysis program of protein sequences (IntelliGenetics).
2. Analysis by RP-HPLC, using a calibrated solution of IGF1 as a Reference Standard.
Greater than 98.0% as determined by:
(a) Analysis by SEC-HPLC.
(b) Analysis by SDS-PAGE.
It is recommended to reconstitute the lyophilized IGF-1 in sterile 0.4% NaHCO3 adjusted, not less than 100ug/ml, which can then be further diluted to other aqueous solutions.
Lyophilized Insulin-Like Growth Factor-1 although stable at room temperature for 3 weeks, should be stored desiccated below -18oC. Upon reconstitution IGF1 should be stored at 4oC between 2-7 days and for future use below -18oC.
For long term storage it is recommended to add a carrier protein (0.1% HSA or BSA).
Please prevent freeze-thaw cycles.
Somatomedin C, IGF-I, IGFI.
