Thymidine phosphorylase activity of platelet-derived endothelial cell growth factor is responsible for endothelial cell mitogenicity

Eur J Biochem. 1993 Feb 15;212(1):201-10. doi: 10.1111/j.1432-1033.1993.tb17651.x.


Recombinant human platelet-derived endothelial cell growth factor, expressed in the yeast Saccharomyces cerevisiae was purified to greater than 98% purity by anion-exchange and hydroxyapatite chromatography. It was shown to possess thymidine phosphorolytic activity in vitro (pH optimum, pH 5.3; Km, 0.11 mM; Vmax, 12.5 mmol min-1 mg-1; turnover number, 9.4 s-1). Covalent modification simultaneously inhibited the enzymatic and mitogenic properties of the protein, while interaction with a cell-surface receptor was not required to stimulate mitogenesis. Purified Escherichia coli thymidine phosphorylase was also mitogenic toward endothelial cells. It is proposed that platelet-derived endothelial cell growth factor is human thymidine phosphorylase which promotes endothelial cell proliferation by reducing thymidine levels that would otherwise be inhibitory to endothelial cell growth.

MeSH terms

  • Cells, Cultured
  • DNA / biosynthesis
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects*
  • Escherichia coli / enzymology
  • Humans
  • Mitogens / pharmacology*
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / pharmacology
  • Saccharomyces cerevisiae / metabolism
  • Thymidine Phosphorylase / metabolism
  • Thymidine Phosphorylase / pharmacology*


  • Mitogens
  • Recombinant Proteins
  • DNA
  • Thymidine Phosphorylase