Insulin-like growth factor-binding protein 4 (IGFBP4)is a member of the insulin-like growth factor binding protein (IGFBP) family. IGFBP4 contains an IGFBP domain and a thyroglobulin type-I domain. It binds both insulin-like growth factors (IGFs) I and II. IGFBPs have been shown to either inhibit or enhance the biological activities of IGF, or act in an IGF independent manner. IGFBP-4 is unique in consistently inhibiting several cancer cells in vivo and in vitro, which suggests that it may act as an apoptotic factor. IGFBP4 is secreted by all colon cancer cells.The human IGFBP4 contains a potential N linked glycosylation site and shares approximately 90% amino acid sequence identity with both the mouse and rat IGFBP4.

·Description
Recombinant Human IGFBP4 produced by transiently transfected human cell is a secreted protein with sequence(Accession#P22692) (Asp22- Glu258) of human IGFBP4 fused with a polyhistidine tag at the C-terminus.

·Quality Control

Purity: Greater than 90.0% as determined by:
(a) Analysis by RP-HPLC.
(b) Analysis by reducing and non-reducing SDS-PAGE Silver Stained gel.
Amino-Acid Sequence:Predicted N terminal amino acid is Asp22.
Endotoxin:Less than 0.1ng/μg (1EU/μg) of rHu IGFBP4.

·Formulation
Sterile and Lyophilized from a 0.2 μm filtered solution in PBS.

·Reconstitution
It is recommended to reconstitute the lyophilized rHu IGFBP4 in sterile water not less than 100μg/ml, which can then be further diluted to other aqueous solutions.

·Storage
Lyophilized rHuIGFBP4 although stable at room temperature for 3 weeks, should be stored desiccated below -18°C. Upon reconstitution rHuIGFBP4 should be stored at 4°C between 2-7 days and aliquots of reconstituted samples containing 0.1% BSA are stable up to 3 months below -18°C for future use.