def sort_amounts(proteins, sort_index):
    amounts = {}
    for protein in proteins:
        amount_x_for_protein = protein[sort_index]
        try:
            amounts[amount_x_for_protein].append(protein)
        except KeyError:
            amounts[amount_x_for_protein] = [protein]
    return [v for k, v in sorted(amounts.items(), reverse=True)]