The IGFBP-4 blood test is still experimental, but Dr.
She also hopes that her studies on IGFBP-4 could lead to new approaches that would improve fetal growth in high-risk pregnancies.
Gruslin and others suggests that IGFBP-4 blocks the activity of a key placental growth hormone called IGF-II, which results in poor growth of the placenta and fetus.
The amino acid sequence of all modified peptides analyzed as candidate substrates was LQKHFAKIRDRSTSGGKMKVNGAPRE, corresponding to residues 118 to 143 of human IGFBP-4 (22).
We synthesized 4 variants (QF-I to -IV) of a 26-residue peptide derived from human IGFBP-4, in which residues 130 to 133 were substituted individually with an o-aminobenzoic acid-modified lysine residue, Lys(Abz), and the glycine residue at position 139 was substituted with a 3-nitrotyrosine residue, Tyr(N[O.sub.2]).
We therefore developed an activity assay based on quenched fluorescence using a synthetic peptide spanning the cleavage site of the PAPP-A substrate IGFBP-4 (Fig.
As one of the members of the IGFs superfamily, IGFBP-4, a nonglycosylated protein of 25 kDa and 32-36 kDa, was first isolated from medium conditioned by human osteosarcoma TE-89 cells (Mohan et al., 1989) and from adult rat serum (Shimonaka et al., 1989).
Commonly, unlike IGFBP1-3, IGFBP-4 inhibits the actions of IGFs, and it can not bind cell surface.
Human IGFBP-4 gene is mapped on chromosome 17, it contains four exons and spans 15.3 kb on chromosome (Allander et al., 1993), recently, we have mapped the porcine IGFBP-4 gene on SSC12 by FISH and RH panel (Wang et al., 2005).
Evidence that the interaction between insulin-like growth factor (IGF)-II and IGF binding protein (IGFBP)-4 is essential for the action of the IGF-II-dependent IGFBP-4
Another inhibitory IGFBP that is increased in some chronic diseases and could impact bone formation is IGFBP-4. This binding protein is principally regulated by parathyroid growth hormone (26).
Serum IGFBP-4, rises dramatically with advancing age in both men and women (33).