Heparin protects heparin-binding growth factor-I from proteolytic inactivation in vitro

Biochem Biophys Res Commun. 1988 Apr 15;152(1):432-40. doi: 10.1016/s0006-291x(88)80732-0.


Heparin inhibits proteolytic digestion of heparin-binding growth factor-I (HBGF-I) by trypsin, plasmin and other proteases. This property is lost after thermal denaturation of HBGF-I, suggesting that a heparin:HBGF-I structural interaction rather than a heparin:trypsin interaction is responsible for the resistance of HBGF-I to digestion with trypsin. Heparin is also able to partially protect HBGF-I from thermal denaturation as demonstrated by the ability of heparin to protect HBGF-I from trypsin digestion. The protective effect of heparin is dependent upon the concentration of heparin as well as temperature and duration of denaturation. Autoradiography of 125I-HBGF-I incubated with human umbilical vein endothelial cells demonstrates near complete protection of HBGF-I from proteolytic modification when the incubation is performed in the presence of heparin. These data suggest that (i) the mechanism of the heparin-induced increase in human endothelial cell number at confluence involves the protection of HBGF-I by heparin against proteolytic inactivation and (ii) heparin provides conformational stability to the proteolytic growth factor which reduces the susceptibility of HBGF-I to denaturation.

MeSH terms

  • Animals
  • Cell Division / drug effects
  • Cells, Cultured
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects
  • Fibroblast Growth Factor 1
  • Growth Substances* / pharmacology
  • Heparin* / pharmacology*
  • Humans
  • Kinetics
  • Mice
  • Peptide Hydrolases / metabolism*


  • Growth Substances
  • Fibroblast Growth Factor 1
  • Heparin
  • Peptide Hydrolases