Control of protein synthesis in a wheat germ cell-free system

Thermostable low molecular weight translational inhibitor was found in wheat germ cell-free extract. The inhibitor was formed during preincubation of wheat S-23 fraction with components of the energy-supplying system (ATP, GTP, phosphoenolpyruvate) in the absence of exogenous mRNA. The inhibitor effectively and irreversibly blocks protein synthesis in both wheat germ and rabbit reticulocyte systems. Our results seem to suggest that the inhibitor can activate wheat endogenous mRNA, which under the standard conditions does not reveal template activity but, once activated, can effectively compete with exogenous mRNA.