| COPPER DEFICIENCY IN NEONATES |
| Copper is required in trace amounts for optimal human nutrition. Although copper deficiency is rare in adults, premature infants have low stores of copper and may suffer from its deficiency. This may lead to anemia and cardiomyopathy, because of failure to synthesize adequate amounts of cytochrome c oxidase and other enzymes, including several cuproenzymes involved in the synthesis of heme. |
| Comment. Copper deficiency can impair ATP production by inhibiting the terminal reaction of the electron transport chain, leading to pathology in the heart, where energy demand is high. Dietary formulae for premature infants must contain adequate copper; cow's milk alone is unsuitable, because it is low in copper. |
| Cytochrome c, a small heme protein that is loosely bound to the outer surface of the inner membrane, shuttles electrons from complex III to complex IV. Each cytochrome c carries only one electron, so the reduction of O2 to 2 H2O by complex IV requires four reduced cytochrome c molecules. The binding of cytochrome c to complexes III and IV is largely
electrostatic, involving a number of lysine residues on the protein surface. Reduction of ferricytochrome c (Fe3+) to ferrocytochrome c (Fe2+) by cytochrome c1, leads to a change in the three-dimensional structure of the protein, promoting transfer of electrons to cytochrome a in complex IV (Fig. 8.5). Under certain conditions (at low membrane potentials), cytochrome c leaks out of mitochondria, inducing apoptosis (cell death).
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