N-acetyl-D-phenylalanine <=> N-acetyl-L-phenylalanine
n-acetyl-d-phenylalanine <=> n-acetyl-l-phenylalanine
N-acetyl-D-phenylalanine <=> N-acetyl-L-phenylalanine
n-acetyl-d-phenylalanine <=> n-acetyl-l-phenylalanine