Winzerling J J, Law J H
Department of Biochemistry, and the Center for Insect Science, University of Arizona, Tucson 85721, USA.
Annu Rev Nutr. 1997;17:501-26. doi: 10.1146/annurev.nutr.17.1.501.
The suggestion from nutritional studies with mammals of a link between iron and copper metabolism has been reinforced by recent investigations with yeast cells. Iron must be in the reduced ferrous (FeII) state for uptake by yeast cells, and reoxidation to ferric (FeIII) by a copper oxidase is part of the transport process. Thus, yeast cells deficient in copper are unable to absorb iron. In an analogous way, animals deficient in copper appear to be unable to move FeII out of cells, probably because it cannot be oxidized to FeIII. Invertebrate animals use copper and iron in ways very similar to vertebrates, with some notable exceptions. In the cases where vertebrates and invertebrates are similar, the latter may be useful models for vertebrate metabolism. In cases where they differ (e.g. predominance of serum ferritin in insects, oxygen transport by a copper protein in many arthropods, central importance of phenoloxidase, a copper enzyme in arthropods), the differences may represent processes that are exaggerated in invertebrates and thus more amenable to study in these organisms. On the other hand, they may represent processes unique to invertebrates, thus providing novel information on species diversity.
近期对酵母细胞的研究进一步证实了哺乳动物营养研究中关于铁与铜代谢之间联系的观点。铁必须处于还原亚铁（FeII）状态才能被酵母细胞摄取，而通过铜氧化酶将其重新氧化为铁（FeIII）是运输过程的一部分。因此，缺乏铜的酵母细胞无法吸收铁。类似地，缺乏铜的动物似乎无法将FeII转运出细胞，这可能是因为它无法被氧化为FeIII。无脊椎动物使用铜和铁的方式与脊椎动物非常相似，但也有一些明显的例外。在脊椎动物和无脊椎动物相似的情况下，后者可能是脊椎动物代谢的有用模型。在它们不同的情况下（例如昆虫中血清铁蛋白占主导地位、许多节肢动物中通过铜蛋白进行氧气运输、节肢动物中铜酶酚氧化酶的核心重要性），这些差异可能代表了在无脊椎动物中被放大的过程，因此更便于在这些生物体中进行研究。另一方面，它们可能代表了无脊椎动物特有的过程，从而提供了关于物种多样性的新信息。
