comparing the activities of the variants with the c-termini-gly-phe-phe ( 36 % ) and -gly-phe-ala ( 36 % ) or -gly-phe-phe-tyr ( 61 % ) and -gly-phe-phe-ala ( 59 % ) , it becomes clear that the aromatic amino acids phe ( b25 ) and tyr ( b26 ) can be substituted by ala without loss of activity .
C0301713
aromatic amino acids
C0031453
phe