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.

蛋内含肽是一个蛋体中的多肽序列，可以催化自身从蛋体中断裂，两侧的蛋显肽连接成成熟的蛋。