IGFBP4 Protein, Human, Recombinant (His Tag)

Insulin-like growth factor-binding protein 4 (IGFBP-4) is a 24-kDa protein that binds insulin-like growth factor 1 (IGF-1) and IGF-2 with high affinity and inhibits IGF action in vitro. The Insulin-like growth factor-binding protein also known as IGFBP serves as a carrier protein for Insulin-like growth factor 1. IGFBPs are distinct but are sharing regions with strong homology. All members of the IGFBP family bind IGF-I and IGF-II with about equal affinity. Insulin-like growth factor (IGF) binding proteins (IGFBPs) have been shown to either inhibit or enhance the action of IGF or act in an IGF-independent manner in the prostate. IGF-binding protein-4 (IGFBP-4) inhibits IGF-I action in vitro and is the most abundant IGFBP in the rodent arterial wall. Expression of IGFBP-4 mRNA in nontransgenic littermates was maximal in the liver and kidney. IGFBP-4 is a functional antagonist of IGF-I action on SMC. There is mounting evidence that the structure of the IGFBP proteins plays a key role in the regulation of IGF bioavailability, by modulating its molecular size, capillary membrane permeability, target tissue specificity, cell membrane adherence, and IGF affinity.

1. Measured by its ability to bind human IGF1 (Cat:10598-H24E) in functional ELISA. 2. Measured by its ability to bind human IGF2 (Cat:13032-H24E) in functional ELISA. 3. Measured by its ability to inhibit the biological activity of IGFI or IGFII on MCF7 human breast adenocarcinoma cells (Karey, K.P. et al. (1988) Cancer Research 48:4083.) . The EDfor this effect is typically 0.04-0.4 μg/mL in the presence of 14 ng/mL human IGFII.

Lyophilized from sterile PBS, pH 7.4. Please contact us for any concerns or special requirements. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween 80 are added as protectants before lyophilization. Please refer to the specific buffer information in the hard copy of CoA.

The secreted recombinant human IGFBP4 comprises 248 amino acids with a predicted molecular mass of 27.4 kDa. As a result of glycosylation, it migrates as an approximately 32 kDa band in SDS-PAGE under reducing conditions.

In general, recombinant proteins are provided as lyophilized powder which are shipped at ambient temperature. Bulk packages of recombinant proteins are provided as frozen liquid. They are shipped out with blue ice unless customers require otherwise. Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.