Allen D W, Burgoyne C F, Groat J D, Smith C M, White J G
Blood. 1984 Dec;64(6):1263-9.
Splenectomized patients with hemoglobin (Hb) Köln have rigid RBCs with membrane polypeptide aggregates that are not dissociable with disulfide-reducing agents. Malondialdehyde (MDA) action on normal RBCs produced rigid RBCs with similar nondissociable aggregates. To test the hypothesis that Hb Köln RBC aggregates contained unsaturated MDA-type bonds, we reduced normal control RBC membranes, Hb Köln RBC membranes, and MDA-reacted membranes with [3H]NaBH4. Hb Köln RBC membranes and MDA-reacted membranes both had significantly more 3H incorporation than control membranes. Furthermore, 3H incorporation in both Hb Köln and MDA-treated membranes was located in the membrane polypeptide aggregates, presumably saturating the crosslinking bonds. After reaction of RBCs with [14C]MDA, the MDA label was similarly concentrated in the membrane polypeptide aggregates. Normal RBC membranes incubated with MDA were analyzed with and without reduction by NaBH4 prior to amino acid determination by high-performance liquid chromatography (HPLC). Reduction with NaBH4 after MDA treatment decreased the lysyl residues by 33% and the serine by 7% and increased by 10% the methionyl residues, but did not affect 12 other amino acids. Similar changes could be detected in NaBH4-reduced Hb Köln aggregates in methionine and serine content. MDA may also alter protein configuration, as evidenced by an increase in the protease susceptibility of membrane proteins from MDA-treated and Hb Köln RBCs. We conclude that Hb Köln RBC membranes, like MDA-treated membranes, have similar high molecular weight aggregates conferring decreased membrane deformability, [3H]NaBH4-reducible unsaturated bonds, changes in amino acid composition upon reduction, and protease-sensitive configurational changes.
患有血红蛋白（Hb）科隆病的脾切除患者的红细胞（RBC）僵硬，其膜多肽聚集体不能被二硫键还原剂解离。丙二醛（MDA）作用于正常红细胞会产生具有类似不可解离聚集体的僵硬红细胞。为了验证Hb科隆病红细胞聚集体含有不饱和MDA型键的假设，我们用[3H]硼氢化钠还原正常对照红细胞膜、Hb科隆病红细胞膜和MDA反应膜。Hb科隆病红细胞膜和MDA反应膜的3H掺入量均显著高于对照膜。此外，Hb科隆病和MDA处理膜中的3H掺入都位于膜多肽聚集体中，可能使交联键饱和。红细胞与[14C]MDA反应后，MDA标记同样集中在膜多肽聚集体中。在通过高效液相色谱（HPLC）测定氨基酸之前，对用MDA孵育的正常红细胞膜进行了有无硼氢化钠还原的分析。MDA处理后用硼氢化钠还原使赖氨酰残基减少33%，丝氨酰残基减少7%，甲硫氨酰残基增加10%，但不影响其他12种氨基酸。在硼氢化钠还原的Hb科隆病聚集体的甲硫氨酸和丝氨酸含量中也能检测到类似变化。MDA还可能改变蛋白质构型，MDA处理的红细胞和Hb科隆病红细胞膜蛋白对蛋白酶的敏感性增加就证明了这一点。我们得出结论，Hb科隆病红细胞膜与MDA处理的膜一样，具有类似的高分子量聚集体，导致膜变形性降低、[3H]硼氢化钠可还原的不饱和键、还原后氨基酸组成的变化以及对蛋白酶敏感的构型变化。
