Effect of Cystine and Methionine on Healing of Experimental Wounds.

The effect of methionine and cystine on the healing index of standard experimental wounds in rats was determined. Since both amino acids have the same effect, per equivalent of sulfur, it is concluded that methionine is converted to cystine before being used in the healing process. When the utilization of methionine is blocked by ethionine, cystine is ineffective, indicating that some methionine, per se, is required for the healing of wounds. There appears to be a correlation between the healing index and the retention of amino acid sulfur in excess of that expected on the basis of nitrogen retention.