factor 1 showed a correlation to alpha-amino-n-butyric acid , valine , methionine , isoleucine , leucine , tyrosine and phenylalanine , factor 2 to lysine , histidine , arginine and glutamine ( containing serine ) , factor 3 to taurine and proline , factor 4 to glycine and cystine , factor 5 to urea and factor 6 to glutamic acid .
C0017797
glutamine
C0061472
glutamic acid