Carotenoid cleavage dioxygenases (CCDs) comprise a superfamily of mononuclear non-heme iron proteins that catalyze the oxygenolytic fission of alkene bonds in carotenoids to generate apocarotenoid products. Some of these enzymes exhibit additional activities such as carbon skeleton rearrangement and trans-cis isomerization. The group also includes a subfamily of enzymes that split the interphenyl alkene bond in molecules such as resveratrol and lignostilbene. CCDs are involved in numerous biological processes ranging from production of light-sensing chromophores to degradation of lignin derivatives in pulping waste sludge. These enzymes exhibit unique features that distinguish them from other families of non-heme iron enzymes. The distinctive properties and biological importance of CCDs have stimulated interest in their modes of catalysis. Recent structural, spectroscopic, and computational studies have helped clarify mechanistic aspects of CCD catalysis. Here, we review these findings emphasizing common and unique properties of CCDs that enable their variable substrate specificity and regioselectivity.

This article is part of a Special Issue entitled Carotenoids recent advances in cell and molecular biology edited by Johannes von Lintig and Loredana Quadro.

类胡萝卜素裂解双加氧酶 (CCDs) 包含一个单核非血红素铁蛋白超家族，可催化​​类胡萝卜素中烯烃键的氧裂解生成类胡萝卜素产物。一些这些酶的表现出额外的活动，如碳骨架重排和反式-顺式异构化。该组还包括一个酶亚家族，这些酶在分子中分裂间苯烯烃键，如白藜芦醇和木质芪。CCD 参与了许多生物过程，从光敏发色团的产生到制浆废污泥中木质素衍生物的降解。这些酶表现出独特的特征，将它们与其他非血红素铁酶家族区分开来。CCD 的独特特性和生物学重要性激发了人们对其催化模式的兴趣。最近的结构、光谱和计算研究有助于阐明 CCD 催化的机制方面。在这里，我们回顾了这些发现，强调了 CCD 的共同和独特的特性，这些特性使其具有可变的底物特异性和区域选择性。

本文是由 Johannes von Lintig 和 Loredana Quadro 编辑的题为类胡萝卜素在细胞和分子生物学方面的最新进展特刊的一部分。