contributions resulting from peptide transitions constitute a large portion of the total dichroism , nevertheless substitution of the non aromatic cycloexylalanine residue in position 8 of the s-peptide with phenylalanine , p-fluorophenylalanine and tyrosine leads to cd negative maxima located at 215 , 215 and 212,5 nm , respectively .
C0031453
phenylalanine
C0030137
p-fluorophenylalanine