Rahmoune H, Chen H L, Gallagher J T, Rudland P S, Fernig D G
School of Biological Sciences, Life Sciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom.
J Biol Chem. 1998 Mar 27;273(13):7303-10. doi: 10.1074/jbc.273.13.7303.
We have determined the relationship between the binding sites for acidic fibroblast growth factor (aFGF) and basic FGF (bFGF) in heparan sulfate (HS) prepared from a panel of mammary cell lines and the ability of the HS to activate aFGF and bFGF in DNA synthesis assays. The ka of the HS for aFGF fell into three groups, whereas the kd (0.0015-0.016 s-1) and the Kd (0.4-8.6 microM) formed a continuum. bFGF possessed a high affinity binding site (Kd 22-30 nM) with a fast ka (320,000-550,000 M-1 s-1), termed "fast/high," and a lower affinity site (Kd 47-320 nM) with a slower ka (35,000-150,000 M-1 s-1), termed "slow/low." Most of the species of HS possessed the latter binding site, which was able to activate bFGF in HS-deficient fibroblasts. However, the HS from the culture medium of the mammary fibroblasts and the myoepithelial-like cells possessed both a fast/high and a slow/low binding site and could not activate bFGF, although it could potentiate the growth-stimulatory activity of aFGF. Treatment of the HS possessing two binding sites for bFGF with heparitinase 1 released oligosaccharides that were able to restore the activity of bFGF in HS-deficient fibroblasts.
我们已确定从一组乳腺细胞系制备的硫酸乙酰肝素（HS）中酸性成纤维细胞生长因子（aFGF）和碱性成纤维细胞生长因子（bFGF）的结合位点之间的关系，以及HS在DNA合成试验中激活aFGF和bFGF的能力。HS对aFGF的ka值分为三组，而kd（0.0015 - 0.016 s-1）和Kd（0.4 - 8.6 microM）形成一个连续体。bFGF具有一个高亲和力结合位点（Kd 22 - 30 nM），其ka值较快（320,000 - 550,000 M-1 s-1），称为“快/高”，以及一个较低亲和力位点（Kd 47 - 320 nM），其ka值较慢（35,000 - 150,000 M-1 s-1），称为“慢/低”。大多数HS种类具有后一种结合位点，该位点能够在缺乏HS的成纤维细胞中激活bFGF。然而，来自乳腺成纤维细胞和肌上皮样细胞培养基的HS同时具有快/高和慢/低结合位点，并且不能激活bFGF，尽管它可以增强aFGF的生长刺激活性。用硫酸乙酰肝素酶1处理具有两个bFGF结合位点的HS会释放出能够恢复缺乏HS的成纤维细胞中bFGF活性的寡糖。
