H-GLU-TYR-GLU-OH

H-ALPHA-GLU-TYR-GLU-OH

ALPHA-L-GLU-L-TYR-L-GLU

L-A-GLUTAMYL-L-TYROSYL-L-GLUTAMIC ACID

L-ALPHA-GLUTAMYL-L-TYROSYL-L-GLUTAMIC ACID

ALPHA-L-GLUTAMYL-L-TYROSINE-L-GLUTAMIC ACID