those always found in readily detectable amounts included o-phosphoserine , taurine , o-phosphoethanolamine , aspartic acid , hydroxyproline , threonine , serine , glutamic acid , proline , glycine , alanine , alpha-amino-n-butyric acid , valine , cystine , methionine , isoleucine , leucine , tyrosine , phenylalanine , ornithine , gamma-amino-butyric acid , lysine , histidine , and arginine .
C0001898
alanine
C0002520
amino