Osaki S, Sexton R C, Pascual E, Frieden E
Biochem J. 1975 Dec;151(3):519-25. doi: 10.1042/bj1510519.
The catalytic activity of phosvitin in Fe(II) oxidation and the addition of iron to transferrin were studied under various conditions. It was concluded that the Fe(II) oxidized by phosvitin would bind to apotransferrin, although an appreciable fraction of Fe(III) remained bound to phosvitin. Fe(III) also migrated from phosvitin to apotransferrin. This reaction was first-order with respect to Fe(III)-phosvitin concentration with a half-time (t1/2) of 10 min, and a first-order rate constant, k=0.069min-1, in 700 muM-phosphate buffer, pH 7.2, at 30 degrees C. The catalysis of the oxidation of Fe(III) by phosvitin was proportional to O2 concentration, and is quite different from the relative O2 independence of Fe(II) oxidation as catalysed by ferroxidase. A scheme for the mobilization and transfer of iron in the chicken, including the role of ferroxidase, phosyitin and transferrin, is presented.
在不同条件下研究了卵黄高磷蛋白在亚铁氧化及向转铁蛋白添加铁方面的催化活性。得出的结论是，被卵黄高磷蛋白氧化的亚铁会与脱铁转铁蛋白结合，尽管相当一部分三价铁仍与卵黄高磷蛋白结合。三价铁也会从卵黄高磷蛋白迁移至脱铁转铁蛋白。在30℃、pH 7.2的700μM磷酸盐缓冲液中，该反应对三价铁 - 卵黄高磷蛋白浓度呈一级反应，半衰期（t1/2）为10分钟，一级速率常数k = 0.069min-1。卵黄高磷蛋白对三价铁氧化的催化作用与氧气浓度成正比，这与铁氧化酶催化的亚铁氧化对氧气相对不依赖的情况有很大不同。本文提出了鸡体内铁的动员和转运方案，包括铁氧化酶、卵黄高磷蛋白和转铁蛋白的作用。
