Structure and function of a new endothelial growth factor from snake venom

Research Project

Project/Area Number	09672262
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Biological pharmacy
Research Institution	Meiji University
Principal Investigator	KOMORI Yumiko Meiji University, Faculty of Pharmacy, Assistant Professor, 薬学部, 講師 (60162070)
Project Period (FY)	1997 – 1998
Project Status	Completed (Fiscal Year 1998)
Budget Amount *help	¥1,500,000 (Direct Cost: ¥1,500,000) Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywords	growth factor / endothelial cell / venom protein
Research Abstract	The heparin-binding dimeric hypotensive factor (HF) was purified from Vipera aspis aspis (Aspic viper) venom [Komori, Y. and Sugihara, H. (1990) Toxicon 28, 359-369]. In this study, the amino acid sequence, and structure and function of HF were elucidated. By electrospray ionization mass spectrometry (ESI-MS), the molecular weight of HF was determined to be 25,072.1. The complete amino acid sequence of HF was determined by Edman sequencing of the S-pyridylethylated HF and its peptides derived from enzymatic digestion. The theoretical molecular mass calculated from the primary structure agrees well with the molecular weight determined by ESI-MS. HF consists of two homogenous monomers bound covalently. The monomer with an N-terminal blocked by pyro-glutamic acid contains 110 amino acid residues including 8 cysteine residues, 2 of which are considered to be involved in intermolecular disulfide bonds. Sequential homology search revealed that the primary structure of HF is similar to that of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) with a sequential homology of 45% and 22%, respectively. When injected intradermally into rat, an increase in capillary permeability was observed with HF or VEGF. On the other hand, only HF exerted a strong hypotensive effect immediately after intravenous injection into rat. Purified HF has a mitogenic effect on endothelial cells. Using bovine aortic endothelial cells (BAEC), the half maximal mitogenic concentration of HF was determined to be 5-5.5 nM (125-138 ng/ml). Similarly, VEGF had a mitogenic concentration at 0.5-1 nM. When incubated with HF and cycloheximide or HF and heparin, the cell growth was inhibited, suggesting that the mechanism of action of HF is similar to that of VEGF.