Heme is an essential cofactor in metazoans that is also toxic in its free state. Heme is synthesized by most metazoans and must be delivered to all cellular compartments for incorporation into a variety of hemoproteins. The heme biosynthesis enzymes have been proposed to exist in a metabolon, a protein complex consisting of interacting enzymes in a metabolic pathway. Metabolons enhance the function of enzymatic pathways by creating favorable microenvironments for pathway enzymes and intermediates, facilitating substrate transport, and providing a scaffold for interactions with other pathways, signaling molecules, or organelles. Herein we detail growing evidence for a mitochondrial heme metabolon and discuss its implications for the study of heme biosynthesis and cellular heme homeostasis.

中文翻译：

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线粒体血红素代谢物：洞悉血红素合成和分布的复杂性。

血红素是后生动物中必不可少的辅因子，其游离态也有毒。血红素是大多数后生动物合成的，必须递送到所有细胞区室才能掺入各种血红蛋白中。已经提出血红素生物合成酶存在于代谢产物中，代谢产物是由代谢途径中相互作用的酶组成的蛋白质复合物。代谢素通过为途径酶和中间体创造有利的微环境，促进底物转运以及提供与其他途径，信号分子或细胞器相互作用的支架来增强酶促途径的功能。本文中，我们详细介绍了线粒体血红素代谢素的越来越多的证据，并讨论了其对血红素生物合成和细胞血红素稳态研究的意义。