Influence of Valine Analogues on Protein Synthesis of Chicken Embryo Myoblasts

The influence of various valine analogues on protein synthesis of chicken embryo myoblasts was examined. Valine and its analogues (D-valine, methylvaline, valinol) were supplemented into Medium 199 containing 20 ng/ml of chicken insulin-like growth factor-I (IGF-I) instead of fetal calf serum (FCS). Influence of branched chain amino acids (isoleucine, leucine, valine) on myoblast protein synthesis was also examined. The levels of valine analogue concentration were based on the valine concentration (213 μM) in Medium 199, and the concentrations of supplements were set at 213 μM (×1 of valine in Medium 199) and 2,130 μM (×10 of valine in Medium 199). Protein synthesis was measured by incorporation of 3H-phenylalanine. Methylvaline, which is one of valine derivatives having a methylated amino group, and D-valine, which is an optical isomer of L-valine, had no influence on myoblast protein synthesis although the concentrations of these compounds were 10-times higher (2,130 μM) than that of valine in Medium 199. Leucine and valine had the potency to increase protein synthesis of chicken embryo myoblasts. The supplementation of valinol, which is one of valine derivatives having a hydrated carboxyl group, with 10-times higher concentration than that of valine in Medium 199, decreased myoblast protein synthesis. These results suggested that valinol could be used as an inhibitor of myoblast protein synthesis.