Cotyledon protein incorporation

Figure 2. Effect of ozone on uptake and incorporation of -leucine into protein by cotton cotyledon leaf discs. Plants were exposed to 0.4 ppm Os for 1 hr, 24 hr prior to experiments. Discs were floated on buffer and incubated in -leucine for up to 4 hr and were then transferred to excess cold leucine to chase the incorporated C-leucine for a subsequent 24 hr period. The data show that ozone-treated tissue incorporated more leucine into protein but do not indicate real differential effects on protein hydrolysis.

Development. The incorporation of j Sj-Met into the polypeptide chains of soluble and membrane fractions were almost linear up to 2 h (data not shown), so all the data were the results of 2 h labeling. As shown in Fig. 3, the incorporation of [35sJ-Met into the polypeptide chains of Cyt f, Cyt b6, and Rieske proteins was very low in the dark-grown cotyledons. 

Upon illumination, rapid incorporation of t35s3-Met into these polypeptides was observed. These results suggest that the low levels of accumulation of polypeptides for Cyt f, Cyt b6, and Rieske proteins in the dark-grown cotyledons were due to the low synthetic activities of these polypeptides. 

Incorporation of applied, radioactive leucine into the mitochondrial proteins of pea cotyledons has been observed within 6 h of the start of imbibition, and it may continue for at least another 18 h [95]. Inhibition of protein synthesis on cytoplasmic ribosomes prevents this synthesis of mitochondrial proteins, whereas inhibition of mitochondrial ribosomes does not. Therefore these new mitochondrial proteins are synthesized in the cytoplasm and not in the mitochondria themselves. But even in the absence of synthesis of new mitochondrial proteins, cytochrome oxidase and malate dehydrogenase levels rise and the mitochondria increase in their respiratory efficiency [74, 95]. Therefore protein... 

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