Isolation of a cytolytic component from <i>naja nigricollis nigricollis</i> (spitting cobra) venom*

Abstract

A cytolytic compound (VIb) was isolated by fractionation of crude venom from Egyptian Cobra Snake, Naja nigricollis nigricollis using Sephadex G-75, followed by CM- Sephadex. The isolated protein has a cytolytic effect on red cells, stable at different temperatures (25 ºC-100ºC) and at different pH ranges (5-9). It is partially pure as indicated by SDS-PAGE, with molecular weight approximately 10 kDa. It has no protease or phospholipase activity. It is a glycoprotein, with maximum absorbance at 280nm. It is non antigenic, with LD50 1.83 mg/ kg body weight. DNA extraction from mouse liver tissue and from hepatocellular carcinoma cell line (HEPG2) gave a single intact band after invitro incubation with VIb, indicating that apoptosis is not involved in the cytotoxic mechanism. Small doses of VIb induced lysis in breast, colon and hepatocellular carcinomas cell lines in tissue culture plates.

Keywords: Naja cytotoxin, Hemolytic, Cytolysis, malignant cells