A human erythrocyte-derived growth-promoting factor with a wide target cell spectrum: identification as catalase

We have reported previously that a factor with a molecular weight of 53,000 under SDS-polyacrylamide gel electrophoresis purified from human erythrocyte extracts promoted the growth of a wide variety of cell types from different species, including T cells, B cells, myeloid leukemia cells, melanoma cells, and mastocytoma cells, as well as normal and transformed fibroblast cells. In the present study, amino acid sequence analysis revealed that this factor has homology with human catalase. The purified factor exhibited catalase activity. Catalases derived from human erythrocytes, bovine liver, Aspergillus niger, and recombinant rat liver catalase are all able to promote the growth of cells. Antibody against human catalase absorbed both the growth-promoting activity and the enzyme activity of the purified factor. In addition, treatment of the factor with an irreversible enzyme inhibitor, aminotriazole, resulted in abrogation of both the growth-promoting activity and enzyme activity. These results indicate that the growth-promoting factor is catalase, and its activity is associated with the decomposition of hydrogen peroxide.