Protein synthesis in aging soybean cotyledons. Loss in translational capacity

Ribosomes and supernatant fractions from soybean cotyledons of different ages were prepared to study the Poly U (polyuridylic acid)-directed phenylalanine incorporation. Ribosomes from younger cotyledons were more effective in phenylalanine incorporation compared to ribosomes from older cotyledons. Similarly, the supernatant fractions from younger cotyledons were more efficient, resulting in enhanced incorporation, than the older cotyledons. Substitution of wheat embryo supernatant fraction for soybean cotyledon supernatant fraction resulted in a several fold increase in amino acid incorporation activity, in ribosomes from all ages of soybean cotyledons. Such increase in activity was particularly significant in the older cotyledons. From these experiments it is concluded that in aging soybean cotyledons there is a loss in translational capacity.