Intein is an intervening polypeptide which can catalytic self-cleavage from a pre-protein accompanied by the concomitant joining of the two flanking polypeptides (the extein) through a peptide bond.

蛋内含是一个蛋前体中的列，可以催化自身从蛋前体中断裂，两侧的蛋外显连接成成熟的蛋。