Bovine milk proteins bind calcium and some bind other metal ions or heme. The examination of heme-binding proteins in colostrum and milk using hemin-agarose beads (HA) showed α-casein, κ-casein and lactoferrin (Lf) to be heme-binding proteins. α-Casein and Lf are iron- and heme-binding proteins, and α- and κ-casein bind to HA, as does Lf. κ-Casein and Lf have higher affinity to zinc ion than does α-casein, and κ-casein and Lf interact with α-casein-immobilized beads (CasB). The addition of α-casein to κ-casein bound to CasB decreased the amount of bound κ-casein compared with in the absence of α-casein, and κ-casein likely increases α-casein self-association. α-Casein binds Lf bound to neither iron nor heme, as shown by experiments with the apo-form. Beads with immobilized poly-l-lysine bind heme but Lf inhibits this binding. These results indicate that α-casein, κ-casein and Lf are both heme- and zinc-binding proteins, and that α-casein interacts with κ-casein and Lf through protein-protein interactions. Additionally, Lf shows higher affinity to hemin than does poly-l-lysine.

牛奶蛋白与钙结合，一些与其他金属离子或血红素结合。使用血红素琼脂糖珠 (HA) 检查初乳和牛奶中的血红素结合蛋白显示 α-酪蛋白、κ-酪蛋白和乳铁蛋白 (Lf) 是血红素结合蛋白。α-酪蛋白和 Lf 是铁和血红素结合蛋白，α-和κ-酪蛋白与 HA 结合，Lf 也是如此。κ-酪蛋白和 Lf对锌离子的亲和力高于 α-酪蛋白，并且κ-酪蛋白和 Lf 与 α-酪蛋白固定珠 (CasB) 相互作用。与不存在 α-酪蛋白的情况相比，将α-酪蛋白添加到与 CasB 结合的 κ -酪蛋白中降低了结合的κ -酪蛋白的量，并且κ-酪蛋白可能会增加α-酪蛋白的自我关联。α-酪蛋白结合 Lf，既不结合铁也不结合血红素，如使用 apo 形式的实验所示。固定多聚赖氨酸的珠子结合血红素，但 Lf 抑制这种结合。这些结果表明α-酪蛋白、κ-酪蛋白和Lf都是血红素和锌结合蛋白，并且α-酪蛋白通过蛋白质-蛋白质相互作用与κ-酪蛋白和Lf相互作用。此外，Lf 对血红素的亲和力高于聚赖氨酸。