Are proteins with the same number of each different amino acid that form them necessarily identical proteins?
Even if many proteins have the similar number of each dissimilar amino acid that form them, for example, 50 alanines, 70 glycines and 20 histidines, the sequences in which these amino acids are connected may be very different. So if two or more proteins are in such condition of numeric similarity for each type of their constituent amino acids, they are not necessarily identical.