Stimulation of C¹⁴-histidine incorporation into protein of isolated diaphragm by nonutilized sugars

¹ Department of Physiology, University of Chicago, Chicago, Illinois

The effect of various sugars on protein synthesis was studied by measuring the incorporation of C¹⁴-histidine into the protein of the isolated diaphragm. In diaphragms from rats fasted 48 hours, histidine-2-C¹⁴ incorporation into muscle protein is directly proportional to the glucose concentration in the incubation medium over the range 0–600 mg %. The ability of other sugars to reproduce this effect of glucose on C¹⁴-histidine incorporation into diaphragm protein was tested. The following were found to be as effective as glucose: d-mannose; d-xylose; d-ribose; l-sorbose. The following were without effect: d-galactose; d-fructose; 3-methyl glucose; d-arabinose; l-arabinose; l-xylose. Only 2-deoxy-d-glucose was inhibitory. The results indicate that sugars not appreciably utilized by muscle (i.e. d-xylose, d-ribose and l-sorbose) can increase protein synthesis. The findings do not support the theory that the positive influence of carbohydrate on protein metabolism derives solely from its ability to increase the energy available for protein synthesis.