【8.3.6】胎儿血红蛋白(Fetal hemoglobin, HbF)

胎儿血红蛋白HbF的结构组成为α2γ2，它O2的亲和力明显高于成人的HbA，这显然有利于胎儿通过胎盘（氧分压大大低于肺）从母亲那里获取O2。HbF与O2亲和力之所以高于HbA，是因为与α亚基结合的γ亚基不能结合BPG。

1. 出生之前表达的血红蛋白与出生后表达的血红蛋白在组成上有所不同 ( Fetal hemoglobin or HbF has a different composition than adult hemoglobin or HbA)
2. 胎儿血红蛋白的主要形式是α2γ2，没有β亚基(HbF exists mainly in α2γ2, without β subunit)
3. HbF由γ亚基取代β亚基，导致HbF几乎结合不了2,3-BPG，从而提高了 它与氧气的亲和力，有利于母亲能在胎盘处心甘情愿地把氧气交给胎 儿( In HbF, the β chains are replaced by γ chains, resulting in an α2γ2 quaternary structure. HbF binds BPG less tightly than maternal HbA and as a result has a higher affinity for O2 than maternal HbA. The higher affinity of HbF for O2 allows oxygen to be transferred across the placenta from the mother to the fetus).

参考资料

• 南京大学 杨荣武老师 《结构生物学》课件