Protein Metabolism of Tissue Cells in vitro.

Abstract

Summary. In continuation of our studies on the dialyzable substances required for the growth of animal tissue cells, extracts prepared from kidney, heart and blood corpuscles have been investigated. The experiments indicate that the active substances present in these extracts are not of the same character as the substances present in the genuine media, since the former cannot completely replace the latter. Dialysates of blood serum are found to contain active components which cannot stand boiling. Similar substances are found in extracts of yeast and barley malt. While the boiled extracts appear to contain a mixture of various nutrients, the active extracts of yeast and malt appear to contain only one or a few closely‐related substances which probably serve as activators for the utilization of the plasma proteins by the cells. These thermolabile accessory growth substances appear to be of a highly hydrophilic character as their adsorption from an aqueous solution is difficult and they are insoluble in pure organic solvents. On the other hand, they are soluble in dilute alcohol. They are not precipitated by mereuric chloride at neutral reaction. The significance of these findings to the understanding of the protein metabolism of the tissue cells is discussed. The studies here reported have been carried out with the aid of grants from the National Association for the Control of Cancer, King Christian X's Foundation and Danmarks tekniske Højskoles Fond for teknisk Kemi.