Leucine incorporation into tissue proteins

Despite a significantly greater uptake of C-leucine by ozonated tissue, greater incorporation of leucine into protein does not appear to occur. When incorporation into protein is expressed as a percentage of actually taken up, there is no difference between the untreated and ozone-treated tissue (Table II). These data further support the notion that enhanced uptake is solely a function of increased transport and not of increased internal utilization. 

Metabolic Transit. Free Amadori Compounds. It is well known that the synthetic Amadori compounds of the free amino acids are absorbed by the intestine and excreted unchanged in the urine (9,28,30). The transport is not active as observed with deoxyfructosyltryptophan (30) and c-deoxyfructosyllysine (40), and the level of absorption depends on the nature of the amino acid and on the conditions of ingestion. Nutritional assays and metabolic transit studies performed with radioactive Amadori compounds of tryptophan (12,30), leucine (12), and lysine (9,28,41) given orally or intravenously on normal or anti-biotics-treated animals have shown that the intestinal microflora can regenerate part of the amino acid. This can be absorbed subsequently at a very low level by the caecum or the large intestine and incorporated into the tissue proteins or utilized by the intestinal microflora. Barbiroli (13) showed also that some intestinal enzymes were able to liberate some amino acids from their Amadori compounds but to a very small... 

Srivastava, U., and Berlinguet, L., Biochemical changes in progressive muscular dystrophy. V. Incorporation of leucine-C into protein of various tissues of normal and dystrophic mice. Arch. Biochem. Biophys. 114, 320-325 (1966). 

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.

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