Amino acid studies in the transformation of proteins of the hen's egg to tissue proteins during incubation.

hhderhalden and Kempe (1) analyzed the hen’s egg for glutamic acid, glycine, and tyrosine on the lst, lOth, and 21st day of incubation. Their results indicated that the amounts of these acids remained constant throughout the incubation period. Investigations carried out by Calvery (a-4), Plimmer and Lowndes (5), Schenck (6), and Sendju (7, 8) indicate that variations occur in the amounts of arginine, histidine, lysine, tryptophan, and tyrosine contained in the egg as the chick embryo develops. However, there exists wide disagreement as to the nature of these changes. Studies on the distribution of amino acids in the incubated hen’s egg have not been reported since 1932, therefore the more modern techniques of amino acid analysis have not been applied. Furthermore, the distribution of several of the amino acids in the egg has never been investigated at all. Because of the disagreement among previous investigators and of the limited number of amino acids studied, a study by means of microbiological assay has been undertaken to review the distribution of arginine, histidine, lysine, tryptophan, and tyrosine in the white, yolk, and embryo of the developing hen’s egg. The amino acids aspartic acid, glutamic acid, glycine, isoleucine, leucine, methionine, phenylalanine, threonine and valine, not previously studied in the various components (white, yolk, embryo), have been included in the present investigation.