红细胞外HbA_2与HbA间的相互作用

 1.为了阐明血红蛋白A_2现象的发生机制,研究了红细胞外Hb A_2与HbA有无相互作用。结果表明,这些血红蛋白在离开红细胞后仍能发生相互作用。 2.我们是用交叉电泳来验证这个问题,主要实验结果如下: (1)单向交叉电泳结果表明,溶血液HbA穿过另一溶血液的Hb A_2时,出现明显的交叉电泳图象。 (2)双向交叉电泳实验使上述结果更加明确。 (3)用提纯的Hb A做实验,证实了Hb A与Hb A_2间的相互作用。 (4)血浆白蛋白穿过Hb A_2、Hb A及CA时,没有看到交叉电泳图象。说明Hb A与Hb A_2之间的作用是特异的。 4.初步结论,不仅在缸细胞中Hb A_2是与Hb A结合存在,就是在离开红细胞的条件下,这两种血红蛋白之间仍能发生相互作用。我们认为,这就是血红蛋白A_2现象的发生机制,很可能如此。     

血红蛋白A2现象发生机制的研究——“红细胞HbA2”为HbA2与HbA的结合产物

为了弄清血红蛋白A₂现象的发生机制,我们对“红细胞HbA₂”的化学组成进行了分析。“红细胞HbA₂”的双向电泳结果表明,它含有两种血红蛋白成分:一种相当于HbA,另一种很可能是溶血液HbA₂。其单向二次电泳结果也证明,它是由溶血液HbA₂和HbA所组成。结果初步说明,盘红细胞中HbA₂可能与HbA结合存在。两者可能有相互作用,也许这是产生血红蛋白A₂现象的原因。     

血红蛋白A_2现象 Ⅰ.A_2现象的发现及其初步应用

1.本文报告作者实验室所发现的一种自然现象,并暂时命名为“血红蛋白A_2现象”。2.所谓“血红蛋白A_2现象”,就是溶血液中HbA_2与红细胞中“HbA_2”的差异。这里主要指的是电泳行为不同。3.将正常成人红细胞与其本身的溶血液并排电泳(薄层淀粉胶电泳)时,二者的HbA、碳酸酐酶电泳位置相同,只有HbA_2不一样。与溶血液中HbA_2相比,红细胞中的“HbA_2”电泳速度(向阳极)稍快。4.红细胞及溶血液中的HbF、HbN包头、HbD包头及HbE,都没有上述差异,而且它们对“HbA_2现象”没有影响。5.“HbA_2现象”的机制尚待阐明,但已经发现了它的应用。众所周知,HbE与A_2的电泳行为及层析性质是相同或相近的,鉴别起来比较困难,现在我们可以利用“HbA_2现象”来区分这两种血红蛋白。如上所述,HbA_2有“HbA_2现象”,而HbE本身则没有这类现象。     

血红蛋白 A_2现象——Ⅰ.A_2现象的发现及其初步应用

1.本文报告作者实验室所发现的一种自然现象,并暂时命名为“血红蛋白A_2现象”。2.所谓“血红蛋白A_2现象”,就是溶血液中HbA_2与红细胞中“HbA_2”的差异。这里主要指的是电泳行为不同。3.将正常成人红细胞与其本身的溶血液并排电泳(薄层淀粉胶电泳)时,二者的HbA、碳酸酐酶电泳位置相同,只有HbA_2不一样。与溶血液中HbA_2相比,红细胞中的“HbA_2”电泳速度(向阳极)稍快。4.红细胞及溶血液中的HbF、HbN 包头、HbD 包头及HbE,都没有上述差异,而且它们对“HbA_2现象”没有影响。5.“HbA_2现象”的机制尚待阐明,但已经发现了它的应用。众所周知,HbE 与A_2的电泳行为及层析性质是相同或相近的,鉴别起来比较困难,现在我们可以利用“HbA_2现象”来区分这两种血红蛋白。如上所述,HbA_2有“HbA_2现象”,而HbE 本身则没有这类现象。     

活体红细胞内血红蛋白的电泳释放

当今的蛋白质组学研究,都是先裂解细胞放出蛋白质,然后对蛋白质溶液进行各种分析.对于红细胞来说,它的裂解产物也称＂溶血液＂,其中主要成分有血红蛋白A1,A2,A3和碳酸酐酶（CA）等.本实验室用未裂解的完整的活体红细胞直接进行电泳,观察其释放出来的血红蛋白（hemoglobin,Hb）,建立了淀粉-琼脂糖混合凝胶中红细胞的电泳释放实验.电泳释放可分为＂初释放＂（一次通电完成电泳,此时有Hb释放出来）和＂再释放＂（电泳过程中断电-再通电,又有Hb释放出来）.本实验室在＂初释放＂实验中发现了＂HbA2现象＂,并通过Hb交叉电泳发现了HbA2与HbA1的相互作用;利用初释放型双向对角线电泳发现红细胞内HbA2与HbA1结合存在;对电泳释放出来的＂HbA2现象＂成分做SDS-PAGE及质谱分析,发现Prx-2（Peroxiredoxin-2）可能参与＂HbA2现象＂的形成;在研究＂再释放＂实验中发现了＂Hb多带再释放现象＂,在此基础上创建等渗再释放、低渗再释放、等低渗全程再释放及再释放型双向对角线电泳;两种红细胞（全血中的红细胞和由它分离出来的游离红细胞）再释放的比较研究;血浆成分对红细胞再释放的影响等.以上研究方法的建立为活体细胞内蛋白质存在状态的研究提供了基础,并开辟了新的研究途径和领域.     

少年游泳运动员冬训期间HbA_2百分含量的规律性变化

 本研究用聚丙烯酰胺凝胶垂直板电泳,双波长扫描仪对少年游泳运动员的HbA_2百分含量进行测定。发现大运动量训练对HbA_2水平是有影响的。经六天训练(星期二、五为大运动量训练),星期日休息一天,次周的星期一晨HbA_2百分含量升高,星期二大运动量训练后的次日晨HbA_2百分含量显著下降。运动性贫血的运动员,其HbA_2百分含量一周中的变化趋势与正常运动员相似,但HbA_2百分含量比正常运动员高。     

MCH、MCV、RDW-CV、HbA_2和红细胞脆性试验在地中海贫血和缺铁性贫血鉴别诊断中的应用

目的:探讨平均红细胞血红蛋白量(MCH)、平均红细胞体积(MCV)、红细胞分布宽度变异系数(RDW-CV)、血红蛋白A_2(Hb A_2)和红细胞脆性试验在地中海贫血和缺铁性贫血鉴别中的价值。方法:以地中海贫血基因诊断和血清铁蛋白测定作为确诊地中海贫血和缺铁性贫血的分组依据,选择2012年1月1日至2014年12月31日广州军区总医院经分子生物学和血清铁蛋白检测的156例患者为研究对象,将其分为地中海贫血组115例(其中α地中海贫血77例,β地中海贫血37例,α地中海贫血复合β地中海贫血1例)和缺铁性贫血组41例;比较患者的MCH、MCV、RDW-CV、Hb A_2和红细胞脆性等血液学指标,采用ROC曲线评价鉴别地中海贫血和缺铁性贫血的血液学指标,试找出最适合鉴别这2种贫血的截断值(cut-off值),以截断值计算上述血液学指标鉴别这2种贫血的灵敏度、特异性、预测值与准确率。结果:地中海贫血患者与缺铁性贫血患者的MCH、MCV和红细胞脆性差异有统计学意义(P0.05),RDW-CV差异无统计学意义(P0.05)。MCH、MCV和红细胞脆性的ROC曲线下面积依次为0.641、0.654、0.778,其最佳截断值分别为23.65 pg、72.8 f L、43.5%;MCH、MCV和红细胞脆性试验在鉴别地中海贫血和缺铁性贫血中的灵敏度分别为89.84%、83.94%、80.42%。Hb A_2在α地中海贫血患者与缺铁性贫血患者间差异无统计学意义(P0.05);Hb A_2在β地中海贫血患者与缺铁性贫血患者间差异有统计学意义(P0.001),Hb A_2在ROC曲线下面积为0.925,最佳截断值为2.93%,鉴别β地中海贫血和缺铁性贫血的灵敏度为92.50%。结论:用MCH、MCV、Hb A_2、红细胞脆性试验最佳截断值对鉴别地中海贫血和缺铁性贫血有一定的价值;Hb A_2在鉴别α地中海贫血和缺铁性贫血中无意义;Hb A2鉴别β地中海贫血和缺铁性贫血的灵敏度高。     

血红蛋白S和δβ~+地中海贫血双重杂合子的研究

本文报道一种新型的血红蛋白病。患者出生于也门民主人民共和国,女性,23岁。有腹痛和镰状细胞特征,其红细胞内含有大约15％HbA、18％HbF、1.8％HbA_2和15％慢速血红蛋白。结构分析证明,慢速泳动的血红蛋白是血红蛋白S,β_(6Glu-Val)。因此认为病人是血红蛋白S和δβ~+地中海贫血基因的双重杂合子。本病在世界上首例发现。我们对本病进行了诊断,并从分子遗传学和分子病理学方面进行了讨论。     

高原鼢鼠和高原鼠兔血液参数和血红蛋白亚型对不同海拔生境的响应

高原鼢鼠和高原鼠兔是青藏高原特有的物种,对高原低氧环境有很强的适应性。本研究测定了不同海拔的高原鼢鼠和高原鼠兔的红细胞数目、血红蛋白浓度、平均红细胞压积、平均红细胞体积等;通过质谱测序明确两种高原动物血红蛋白亚型;采用PAML4.8程序分析两种动物血红蛋白亚基中的正向选择位点;采用同源建模的方法分析正向选择位点对血红蛋白氧亲和力的影响,基于对两种高原动物血液特征的分析,探讨了它们适应低氧的策略。结果表明,随着海拔升高,高原鼢鼠通过增加红细胞数目、减小红细胞体积应答低氧,相反,高原鼠兔通过减少红细胞数目、增大红细胞体积应答低氧;高原鼠兔红细胞中具有α₂β₂成年型血红蛋白和α₂ε₂胎儿型血红蛋白,高原鼢鼠红细胞中只有α₂β₂成年型血红蛋白,但高原鼢鼠血红蛋白氧亲和力和别构效应显著高于高原鼠兔;高原鼢鼠与高原鼠兔的血红蛋白α和β亚基中,正向选择的氨基酸位点数目、位置以及它们的侧链基团极性和取向具有明显不同,这可能是造成两种动物血红蛋白氧亲和力不同的重要原因。总之...     

五步蛇蛇毒磷脂酶A_2的纯化及部分性质

经Sephadex G-75和QAE-Sephadex A-50离子交换层析等方法,从湖南产五步蛇(Agkistrodon acutus)蛇毒中纯化一种均一的酸性磷脂酶A_2。SDS-PAGE测得分子量为15.8kD,按氨基酸残基计算其分子量为14.352kD,IEF-PAGE测得等电点为5.32。氨基酸组份分析表明磷脂酶A_2分子由128个氨基酸残基组成,富含Asp和Glu,不含中性糖。PLA_2酶活性的最适温度为45℃,最适pH为8.5左右,没有抗胰蛋白酶的活性,具一定的热稳定性。K~+、Ca~(++)和Na~+离子激活,而Cd~(++)、Sn~(++)、Cu~(++)、Li~+、Hg(++)、Zn~(++)、Fe~(++)和Co~(++)离子可抑制或完全丧失酶活力。手工微量顺序分析测得PLA_2分子N-末端氨基酸为Leu。此酶对小白鼠的LD_(50)至少大于10mg/kg(ip)。     

Further resolution of adult chick hemoglobins by isoelectric focusing in polyacrylamide gel.

Evidence is presented that adult chick hemoglobins exist in four types separable by isoelectric focusing on polyacrylamide gels instead of the two hemoglobin types previously resolved by other methods. These are hemoglobin A1 (HbA1), hemoglobin A2 (HbA2), hemoglobin D1 (HbD1), and hemoglobin D2(HbD2). Their pI values are 7.53 +/- 0.02, 7.37 +/- 0.02, 6.92 +/- 0.04 and 6.72 +/- 0.05, respectively, constituting about 63, 14, 18 and 5% of the total hemoglobin from adult chick erythrocytes, respectively. HbA1 and HbA2 ar identical in size, as determined on sodium dodecyl sulfate gels and similar in their amino acid composition and tryptic peptides. The molecular weight and amino acid composition of HbD1 and HbD2 are also identical although there are differences in their tryptic peptides. Experiments were done to show that the existence of four hemoglobin types is not due to genetic heterogeneity of the experimental animal, nor to artifacts of oxidation of carboxyhemoglobin to methemoglobin tetramers. Care was exercised to eliminate deamination and modification of side chain amino groups by using freshly prepared hemolysates and to minimize the "plateau phenomenon" peculiar to isoelectric focusing by controlling the duration of electrophoresis. The use of cyanmet form of (thus liganded) hemoglobin in this study reduced the chance of heterotetramer formation. Furthermore, consideration was given to possible anomalies caused by ampholytes. In the face of negative evidence for artifacts, it is concluded that adult chicken has more than the two hemoglobin types previously reported.     

The primary structure of alpha A- and beta-chains from blue-and-yellow macaw (Ara ararauna, Psittaci) hemoglobin. No evidence for expression of alpha D-chains

The hemoglobin A of the Blue-and-Yellow Macaw (Ara ararauna) was isolated and characterized. The complete amino-acid sequence of alpha A- and beta-chains is presented. In contrast to some adult avian hemoglobins already investigated, Blue-and-Yellow Macaw hemoglobin is homogenous and contains only one component: HbA. The minor component, HbD, which is usually present in the hemolysate of avian erythrocytes, could not be detected. There is no evidence for the expression of the alpha D-globin gene. Comparison of alpha A- and beta-chains from Blue-and-Yellow Macaw hemoglobin with corresponding chains from Greylag Goose hemoglobin shows 19 amino-acid exchanges between alpha A-chains and 6 between beta-chains. The structure-function relationships of hemoglobin chains and the evolutionary aspects are discussed in view of these results.     

Effect of acylphosphatase on human erythrocyte membrane Ca2(+)-ATPase

We studied the effect of human acylphosphatase on the activity of human erythrocyte membrane Ca2(+)-ATPase. Both the acylphosphatase that is contained in hemolysate and the purified enzyme isolated from red blood cells were able to stimulate Ca2(+)-ATPase activity in erythrocyte membranes. Given the same acylphosphatase activity, however, the hemolysate showed higher stimulatory effect than the purified enzyme. Acylphosphatase stimulation was additive to that induced by calmodulin, thus indicating that acylphosphatase acts in a calmodulin-independent manner. Trifluoperazine, a calmodulin antagonist, did not inhibit acylphosphatase-induced stimulation of Ca2(+)-ATPase activity. Acylphosphatase significantly decreased the rate of Ca2+ influx into inside-out erythrocyte membrane vescicles, thus acting as Ca2+ pump inhibitor. Taken together these findings indicate that acylphosphatase is a soluble, non-calmodulin activator of erythrocyte membrane Ca2(+)-ATPase and might be involved in the control of calcium transport across the plasma membrane.     

Novel approach for the analysis of glycated hemoglobin using capillary isoelectric focusing with chemical mobilization

In this work, a novel CIEF methodology for the analysis of the glycated hemoglobin, HbA(1c), in dimethylpolysiloxane coated fused-silica capillaries (DB-1, 50 microm I.D., 27 cm, 0.20 microm coating thickness), using a narrow pH ampholyte mixture (4% pH 6-8:pH 3-10, 10:1, v/v) in 0.30% methylcellulose, was developed. In the focusing procedure, a 0.100-mol l(-1) phosphoric acid solution was used as anolyte and a 0.040-mol l(-1) NaOH solution was used as catholyte. During method development, two types of mobilization of the focused hemoglobins were tested: pressure and chemical mobilization. Chemical mobilization performed better, allowing the complete baseline resolution of the hemoglobin of interest, HbA(1c), from its adjacent peak, HbA, in less than 8 min. In the chemical mobilization procedure, the catholyte was replaced by a 0.040-mol l(-1) NaOH solution containing 0.080 mol l(-1) NaCl. The proposed methodology was applied to the analysis of 31 hemolysate samples and validated with respect to the selectivity, inter-assay and intra-assay precision (both migration time and hemoglobin percentage concentration). In addition, HbA(1c) determinations were compared for the CIEF method and a chromatographic standardized procedure using cation-exchanger columns (Variant, Bio-Rad), adopted in a local clinical laboratory, showing excellent correlation (r(2)=0.872, n=31). The slope was found to be statistically equal to one but the intercept differed from zero. Also the Bland-Altman plot indicates bias, implying that the CIEF method yields HbA(1c) concentration higher than the reference method. The separation of the hemoglobins HbA, HbA(2), HbF and HbA(1c) and the variants HbS and HbC was also demonstrated (8 min run). The resolving power of the proposed CIEF method allowed baseline resolution of hemoglobins with a pI difference as small as ca. 0.03, as it is the case for the pairs HbC/HbA(2) and HbA/HbA(1c).     

Studies on subfractions of hemoglobin A1b and hemoglobin A1c in diabetic subjects

Hemoglobin (Hb) obtained from the hemolysate of normal subjects and diabetic patients was separated into HbA1a1, HbA1a2, HbA1b, HbA1c and HbA0 (major Hb) by Bio-Rex 70 cation exchange column chromatography. The glycosylated Hbs were further separated reproductively by cation exchange high performance liquid chromatography (HPLC), using 50 mM sodium phosphate buffer pH 5.80 with 0-0.2 M NaCl linear gradient system. HbA1b and HbA1c were separated into two subfractions (HbA1b1 and HbA1b2) and three subfractions (HbA1c1, HbA1c2, HbA1c3), respectively. The percentages of each subfraction except HbA1c1 in diabetic patients were significantly higher than those in normal subjects. Furthermore, HbA1c1, HbA1c2 and HbA1c3 correlated well with fasting blood glucose levels in the prior 5 month period, while subfractions in HbA1b revealed no significant correlation with blood glucose levels. The percentages of each subfraction of HbA1c in patients either with diabetic cataracts or with diabetic neuropathy were almost the same as those in the patients without complications. However, the percentages of each of the three groups were markedly higher than those of the normal subjects. These results suggest that glycosylation of hemoglobin in diabetic patients may be increased in various sites of the molecule in parallel with the blood glucose levels during the preceding 4-5 months.     

Hemoglobin of the adult white stork (Ciconia ciconia, ciconiiformes). The primary structure of alpha A- and beta-chains from the only present hemoglobin component

The hemolysate obtained from erythrocytes of the adult White Stork (Ciconia ciconia) contains only one hemoglobin component, identified to be HbA. The complete primary structures of alpha A- and beta-chains are presented. The minor hemoglobin component HbD with alpha D-chains usually present in adult avian species was not detected by the White Stork. The sequence was determined by automatic Edman degradation of tryptic peptides and in the case of beta-chains additionally of the C-terminal peptide obtained by chemical cleavage at the Asp-Pro bond. Homologous comparison with the Greylag Goose (Anser anser) hemoglobin showed that the alpha A-chains differ by 23 amino-acid exchanges, the beta-chains by 17. Four of the substitutions in the alpha A-chains are in the alpha 1 beta 1-contact points, one in the alpha 1 beta 2-contacts and one in the amino acids near the heme. The amino-acid substitutions of the White Stork hemoglobin as compared to the other avian hemoglobins are discussed. We suggest that alpha D-chain is persistence of an embryonic gene.     

Striped mullet (<Emphasis Type="Italic">Mugil cephalus)</Emphasis> hemoglobin system: multiplicity and functional properties

The most frequent (90%) phenotype of the hemoglobin system of M. cephalus presented two major hemoglobins, the more anodal HbI accounting for approximately 70% of the total. The two hemoglobin components separated by ion-exchange chromatography were analyzed by reverse-phase HPLC and electrospray ionization-mass spectrometry which revealed a more complex pattern: HbI consists in four different globins, two β (named β1 and β3) and two co-eluting α chains (α1 and α2); HbII consists in three globins, one β chain (named β2) and the same α1 and α2 present in HbI. The oxygen-binding properties of both hemoglobin components purified by DEAE cellulose were almost identical to those of the hemolysate: stripped hemoglobin showed a large Bohr effect which was enhanced by chloride ions and, at a larger extent, by organic phosphates which, at acidic pH values gave rise to the Root effect. A series of oxygen-binding experiments at increasing GTP concentrations was carried out in order to compare GTP-binding activities in the absence and presence of physiological amounts of chloride. The results indicated that hemoglobin do have two sites for GTP binding. In the absence of chloride, the two sites cannot be discriminated, whereas in the presence of chloride, a competition between the two anions occurred for both GTP-binding sites. The presence of multiple hemoglobin components with identical properties confirms that hemoglobin heterogeneity that often occurs in fish cannot be only explained as an evolutionary response to the physiological and/or environmental needs of the species.