红细胞摄取二氧化碳并释放氧气
中文名称
通路描述
血浆中的二氧化碳被碳酸酐酶 IV（位于内皮细胞顶膜上的 CA4）水化生成质子（H+）和碳酸氢盐（HCO3-）。血浆二氧化碳也被红细胞通过 AQP1 和 RhAG 摄取。在红细胞内，CA1 和主要 CA2 将二氧化碳水化生成碳酸氢盐和质子（参见 Geers & Gros 2000, Jensen 2004, Boron 2010）。碳酸氢盐通过带 3 阴离子交换蛋白（AE1, SLC4A1）被转移出红细胞，该蛋白协同转运氯离子（Cl-）进入红细胞。此外，在红细胞内，二氧化碳与 HbA 的 N 端α氨基结合形成羰基，而质子与 HbA 中的组氨酸残基结合。净结果是 Bohr 效应，即 HbA 构象变化，降低其对 O2 的亲和力，从而协助向组织输送 O2。
英文描述
Erythrocytes take up carbon dioxide and release oxygen Carbon dioxide (CO2) in plasma is hydrated to yield protons (H+) and bicarbonate (HCO3-) by carbonic anhydrase IV (CA4) located on the apical plasma membranes of endothelial cells. Plasma CO2 is also taken up by erythrocytes via AQP1 and RhAG. Within erythrocytes CA1 and, predominantly, CA2 hydrate CO2 to HCO3- and protons (reviewed in Geers & Gros 2000, Jensen 2004, Boron 2010). The HCO3- is transferred out of the erythrocyte by the band 3 anion exchange protein (AE1, SLC4A1) which cotransports a chloride ion (Cl-) into the erythrocyte.
Also within the erythrocyte, CO2 combines with the N-terminal alpha amino groups of HbA to form carbamates while protons bind histidine residues in HbA. The net result is the Bohr effect, a conformational change in HbA that reduces its affinity for O2 and hence assists the delivery of O2 to tissues.
Also within the erythrocyte, CO2 combines with the N-terminal alpha amino groups of HbA to form carbamates while protons bind histidine residues in HbA. The net result is the Bohr effect, a conformational change in HbA that reduces its affinity for O2 and hence assists the delivery of O2 to tissues.
所含基因
12 个基因