amino_acid_masses = {
    'A': 71.0788,
    'R': 156.1875,
    'N': 114.1038,
    'D': 115.0886,
    'C': 103.1388,
    'E': 129.1155,
    'Q': 128.1307,
    'G': 57.0519,
    'H': 137.1411,
    'I': 113.1594,
    'L': 113.1594,
    'K': 128.1741,
    'M': 131.1926,
    'F': 147.1766,
    'P': 97.1167,
    'S': 87.0782,
    'T': 101.1051,
    'W': 186.2132,
    'Y': 163.1760,
    'V': 99.1326
}