Studies on the incorporation of 14 C-labelled amino acids into egg proteins |
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| Authors: | D N Salter M E Coates D R Westgarth |
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| Institution: | National Institute for Research in Dairying , University of Reading , Reading, RG2 9AT |
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| Abstract: | The incorporation of 14C‐labelled amino acids into egg white and yolk proteins has been studied. When the labelled amino acids were given intravenously as a hydrolysate of U‐14C]‐protein from Chlorella, 10 per cent and 7 per cent of the 14G were recovered in the whites and yolks respectively of the first nine eggs laid. Differences in the specific activities of the conalbumin, the ovalbumins, ovomucoid, “postalbumins “ and lysozyme, isolated from the first active egg, were related to differences in amino acid composition. The specific activity of each amino acid prepared from the proteins was similar between different proteins, although within each protein specific activities of different amino acids varied widely. The proportionate rate of decrease of specific activity in the plasma of amino acids essential for egg production (except glycine) was constant or almost so, but it rapidly decreased for the non‐essential ones (except serine and proline). The specific activities of the amino acids, excepting aspartic and glutamic acids, in each protein were proportional to their mean specific activities in the plasma throughout the 24‐h period in which the egg white proteins were synthesised. It is concluded that these different proteins are synthesised from a shared amino acid pool, derived from plasma, at a rate which probably remains constant throughout the egg‐laying cycle and which is proportional to their content in the albumen. |
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