This disclosure provides peptides, polypeptides, fusion polypeptides, compositions, and methods for enhancing or increasing the stability of a polypeptide (e.g., Taq polymerase). Such peptides, polypeptides, fusion polypeptides, or compositions include polypeptides linked to a peptide tag that enhances the stability of the polypeptide. The peptides, polypeptides, fusion polypeptides, compositions may also enhance the activity, specificity, and/or fidelity of other polypeptides in a reaction mixture. The disclosure also provides methods of using such peptides, polypeptides, fusion polypeptides, compositions.