Objective： Our aim was to purity the modifier protein of glyceraldehyde-3-phosphate dehydrogenase　(G3PD)　from African green monkey Vero-E6 line. Methods：Exposure of Vero-E6 cells to medium with a reduced K concentration (3.2 mmol/L) stimulated the growth and activation of G3PD. The increase of enzyme activity was mediated by a cytosolic modifier protein that was purified using affinity and anion-exchange high-performance liquid chromatograph. Results：The apparent molecular mass of the protein was 62 kDa. Western blotting and quantiative enzyme-linked immunosorbent assay showed that the amount of modifier protein increased progressively for 2 hours in cells exposed to low-K+ medium, and then returned to the control value, a kinetic profile similar to that the modifier protein is a constituent of renal epithelial cells and accummulated transiently in the low-K+ mitogenic signal. Conclusion: We obtained a modifer protein from monkey kidney epithelial cells (Vero-E6). It could activate G3PD and cell growth.