def aa_weight(seq):
    """
    Return molecular weight of amino acid sequence (g/mol).

    Args:
        seq (str): Nucleotide sequence

    Examples:
        >>> sequtils.aa_weight('AGGATAAG')
        700.8
    """
    wmap = {'A': 89.1, 'R': 174.2, 'N': 132.1, 'D': 133.1, 'C': 121.2, 'E': 147.1, 'Q': 146.2, 'G': 75.1, 'H': 155.2, 'I': 131.2, 'L': 131.2, 'K': 146.2, 'M': 149.2, 'F': 165.2, 'P': 115.1, 'S': 105.1, 'T': 119.1, 'W': 204.2, 'Y': 181.2, 'V': 117.1}
    return sum([wmap[i] for i in seq.upper().replace('*', '')])