Effect of amino acid reutilization in the determination of protein turnover in mice

Using different decay data of "in vivo" pulse-labeled protein, the half-life values of different fractions from mouse liver, heart, striated leg muscle, jejunum and epidydimal fat pads were calculated by considering labeled intracellular amino acid reutilization. This was accomplished by substracting the pool amino acid decay rates from the protein decay rates. The extent of reutilization of these labeled amino acids is considerable as shown by the differences found between the corrected and uncorrected half-life calculations. The half-life values obtained for total protein in liver, striated muscle, heart, duodenum and epidydimal fat pad were: 0.57, 1.81, 2.13, 0.68 and 0.42 days, respectively.