1.3.3.13 0.453 - cyclo(L-Phe-L-His) in 100 mM Tris/HCl buffer, pH 8.0, at 30°C 722172 1.3.3.13 0.69 - cyclo(L-Leu-L-Phe) in 100 mM Tris/HCl buffer, pH 8.0, at 30°C 722172