Parallelism Between Sulfur and Selenium Amino Acids in Protein Synthesis in the Skin of Zinc-Deficient Rats

Summary

Feeding animals a diet low in either zinc or selenium causes an abnormal condition of skin and hair. It has been established (7, 8) that the uptake of L-cystine-³⁵S and L-methionine-³⁵S in the skin protein of the ZnD rats was significantly lower than in the zinc-supplemented pair-fed controls (ZnS), i.e., 30 and 60%, respectively. Studies were made to investigate the parallelism between the sulfur (Met and Cyst) and selenium (Se Met and Se Cyst) amino acids in protein synthesis in the skin from ZnD rats. Results indicate that at 24 hr the specific activity (cpm/mg protein) present in the skin of the ZnD rats was 25 and 58% of that of the pair-fed controls, after injection of L-⁷⁵Se Met and L-⁷⁵Se Cyst, respectively. No significant differences were observed in the ⁷⁵Se content of the liver, kidney and muscle between the two groups, which was also true with the sulfur amino acids. These results clearly establish a parallelism between sulfur and selenium amino acids in protein synthesis and strongly suggest that zinc plays a role in the metabolism of Se Met and Se Cyst in protein synthesis in the skin.