the amino acid n with natural isotopic frequency amounted to a quarter for the basic amino acids , a tenth for the branched chain ones and for the non-essential ones ( glutamic acid , aspartic acid , serine , glycine , alanine , proline ) a third of the total oviduct 14n , the average quota of 15n ' is only 3.6 % , that of the branched chain amino acids 4.5 and that of the non-essential ones 21.1 % .
C0002520
amino acid
C0301714
basic amino acids