Synonyms: L-Serine,N-[N2-[N-[N-[N-[a,b-didehydro-N-methyl-N-[N-[1-oxo-3-(2-pentylphenyl)propyl]-L-threonyl]tyrosyl]-L-leucyl]-D-phenylalanyl]-L-allothreonyl]-L-asparaginyl]-,u-lactone;1-Oxa-4,7,10,13,16,19-hexaazacyclodocosane, cyclic peptide deriv.; FK 224; FR115224