共查询到20条相似文献，搜索用时 15 毫秒
1.
A striking similarity has been found between the composition of peptides obtained from tryptic digestion of normal adult hemoglobin (hemoglobin A) and fetal hemoglobin (hemoglobin F). 相似文献
2.
Hemoglobin of 30 Macaca mulatta monkeys and of 15 Macaca irus monkeys consisted of one electrophoretic component similar to human hemoglobin A. Twenty-one M. irus monkeys had two types of hemoglobin. In 20 animals the hemoglobin resembled human hemoglobin AJ, and in one animal it resembled human hemoglobin AI. 相似文献
3.
Hemoglobin Gun Hill: deletion of five amino acid residues and impaired heme-globin binding 总被引：10，自引：0，他引：10
Hemoglobin Gun Hill, a new variant of adult hemoglobin, was found in a Caucasian and one of his three daughters. The abnormal hemoglobin had only half of the expected number of heme groups. Five amino acid residues appeared to be missing from the beta-globin chains. These residues occur in linear sequence in normal beta-chains in a region involved in heme-globin binding. A deletion of five amino acids in the beta-chains of hemoglobin Gun Hill is postulated. The most likely mechanism for the origin of such a hemoglobin variant would appear to be unequal crossing-over during meiosis. 相似文献
4.
Two populations of North Carolina have been analyzed for hemoglobin patterns by paper electrophoresis. Of 534 Cherokee Indians, both mixed and full bloods, all showed normal hemoglobin. Lumbee Indians of less certain ethnic status had 1.7 percent of hemoglobin S, an equal amount of hemoglobin C, and one possible hemoglobin D trait among 1332 bloods studied. 相似文献
5.
Biosynthesis of hemoglobin Ann Arbor: evidence for catabolic and feedback regulation 总被引：5，自引：0，他引：5
Hemoglobin Ann Arbor, in which arginine replaces leucine in position 80 of the a chain, occurs in aflected individuals in low proportion to hemoglobin A. Biosynthetic studies were perforined on reticulocytes of a patient heterozygous for this hemoglobin. These studies suggested that the low percentage of hemoglobin Ann Arbor is prinlarily due to preferential destruction of the abnormal component. The reduced concentration of alpha Ann Arbor chains was also reflected in a decreased synthesis of normal beta chains. 相似文献
6.
In severe experimental hemorrhagic anemia in hens, the injection of beta-pyracin and Lactobacillus casei factor, alone and in combination, was found to hasten the regeneration of hemoglobin. When these factors were administered together, however, the rise in hemoglobin was much more rapid and the level reached was higher than in the lots administered the factors alone. The hemoglobin levels in the control lots rose above the "pre-bleeding" values and then began an almost immediate decline to approximately the original level. In the lots receiving beta-pyracin and Lactobacillus casei factor, alone or in combination, the hemoglobin levels also rose above the "pre-bleeding" values but were maintained for some time after injections were discontinued before declining to the original values. 相似文献
7.
Hemoglobin switching in sheep and goats: occurrence of hemoglobins A and C in the same red cell 总被引：2，自引：0，他引：2
Sheep and goats switch from the synthesis of hemoglobin A (alpha(2)beta(2)(A)) to hemoglobin C (alpha(2)beta(2)(C)) when made anemic. We have demonstrated the existence of the asymmetrical hybrid hemoglobin, alpha(2)beta(A)beta(C), in the circulating red cells of anemic sheep. These erythroid cells, therefore, synthesized both A and C hemoglobin simultaneously. Thus, the switch appears to be mediated by selective gene expression rather than by a clonal or cellular selective mechanism. 相似文献
8.
Rana catesbeiana tadpoles immunized with the main hemoglobin component of the adult frog of the same species produced precipitating and agglutinating antibodies against the immunogen. After natural metamorphosis, the immunized froglets have as their only major hemoglobin a protein immunologically and electrophoretically different from the major hemoglobin of control froglets. 相似文献
9.
A dimeric hemoglobin was purified from nitrogen-fixing root nodules formed by association of Rhizobium with a nonleguminous plant, Parasponia. The oxygen dissociation rate constant is probably sufficiently high to allow Parasponia hemoglobin to function in a fashion similar to that of leghemoglobin, by oxygen buffering and transport during symbiotic nitrogen fixation. The identification of hemoglobin in a nonlegume raises important questions about the evolution of plant hemoglobin genes. 相似文献
10.
In an examination of the blood of 708 Eskimos, 200 Aleuts, and 44 Indians in Alaska for abnormal types of hemoglobin, only normal hemoglobin A was detected. It may be concluded that abnormal hemoglobins in these races are rare if they occur at all. 相似文献
11.
The structure of an invertebrate, intron-containing globin gene has been determined as part of a study of the evolution of hemoglobin. The gene encoding chain c of Lumbricus terrestris hemoglobin has the two-intron, three-exon structure characteristic of vertebrate globin genes, and the exact positions of the splice junctions are conserved. The two introns interrupting the coding sequence are longer than those of known hemoglobins but shorter than myoglobin introns. The gene encodes a secretory preglobin containing a 16-residue signal peptide, as expected for an extracellular hemoglobin. However, no intron separates the DNA encoding the signal sequence from that of the globin sequence. The 3' untranslated region of the Lumbricus gene is much longer than those of the genes for other hemoglobins and is similar to those found for myoglobins. 相似文献
12.
The synthesis of adult-type hemoglobin was measured in small samples of peripheral blood cells from 9- to 18-week human fetuses. Hemoglobin indistinguishable from hemoglobin A was identified by ion-exchange chromatography, electrophoresis at pH 8.6, tryptic peptide analysis, and the insensitivity of its synthesis to the action of O-methylthreonine. Synthesis of hemoglobin A accounted for 8 to 14 percent of total hemoglobin synthesis and was demonstrated in as little as 10 microliters of fetal blood. These studies provide sensitive methods for the detection of beta chain types in hemoglobin synthesized by the human fetus at midtrimester. If methods to obtain small quantities of fetal blood at midtrimester become available, these techniques should be applicable to the antenatal detection of sickle cell anemia and related hemoglobinopathies. 相似文献
13.
Activation of hemoglobin C synthesis in sheep marrow culture 总被引：6，自引：0，他引：6
Erythropoietin preferentially stimulates hemoglobin C synthesis in suspension cultures of marrow cells from sheep homozygous for hemoglobin A; the amount of synthesis is dependent on the dose of erythropoietin and is blocked by antiserum to erythropoietin. The results provide the first in vitro evidence that erythropoietin mediates the hemoglobin A --> C "switch" in sheep and indicate that bone marrow cultures may be used to investigate the mechanisms involved in the preferential gene activation characteristic of the hemoglobin A --> C system. 相似文献
14.
After administration of glycine-2-(14)C to a patient with thalassemia, the specific activities of heme and globin of F hemoglobin were consistently higher than those of hemoglobin A. After reaching a maximum, the ratio of the specific activity of heme to that of globin remained constant within each hemoglobin. Explanations considered include dilution by preformed subunits, differential turnover of hemoglobins, and possibly more than one heme-synthesizing pool. 相似文献
15.
张容昶 《甘肃农业大学学报》1985,(3)
本文根据国内外有关资料,阐述了牦牛适应少氧环境的生态生理特性,主要表现在胸腔和心、肺脏发达;气管粗短,呼吸、脉搏变化幅度大;血液中红细胞和血红蛋白含量高,血红蛋白类型组成变化较特殊,初生牦牛犊血液中含有早期胎儿血红蛋白等。并对上述特性作了初步分析和讨论。本文为牦牛选育、饲牧管理提供了一些依据。 相似文献
16.
An oxygen-binding hemoglobin localized in the nerves of Tellina alternata (Bivalvia) required 30 minutes to unload oxygen when excised nerves were exposed to pure nitrogen. Neural excitability under these conditions could be sustained only until deoxygenation of the hemoglobin was complete. When the oxygen-combining function of the hemoglobin was abolished with carbon monoxide, the neural excitability ceased within a few minutes of oxygen removal, a response identical to that of hemoglobinless homologous nerves of other bivalves. These results demonstrate that aerobic activity can be supported by the oxygen stored on hemoglobin in microscopic tissues for a considerable time under anoxic conditions. 相似文献
17.
Arabinosylcytosine induces fetal hemoglobin in baboons by perturbing erythroid cell differentiation kinetics 总被引：9，自引：0，他引：9
T Papayannopoulou A Torrealba de Ron R Veith G Knitter G Stamatoyannopoulos 《Science (New York, N.Y.)》1984,224(4649):617-619
Arabinosylcytosine, a compound that inhibits DNA synthesis in rapidly dividing cells, stimulates fetal hemoglobin in adult baboons and produces significant perturbations in the pools of erythroid progenitors. It appears that changes in the kinetics of erythroid cell differentiation rather than direct action on the gamma genes underlie stimulation of fetal hemoglobin in the adult animals in vivo. These results also suggest that chemotherapeutic agents selected for their low carcinogenic or mutagenic potential could be used for therapeutic induction of fetal hemoglobin in patients with sickle cell anemia. 相似文献
18.
The fact that members of the subclass Cyclotomata possess monomeric hemoglobin molecules has been known for some time. Electrophoresis of hemolysates from 12 hagfish (Eptatretus stoutii) revealed five hemoglobin phenotypes with four to six distinct zones of hemoglobin. Each zone is believed to represent a monomer containing one heme group on a single polypeptide chain with a molecular weight of approximately 18,000. It is postulated that these monomers are controlled by genes at four loci. 相似文献
19.
A kinetic model based on allosteric mechanisms of cooperativity fits the experimentally observed phosphate dependence of hemoglobin reactions. Subunit inequivalence is found to be important in analyzing hemoglobin kinetics. The observed increase in the rate of deoxygenation in the presence of organic phosphates is primarily related to the increased rate of dissociation of the second oxygen molecule. 相似文献
20.
Cat hemoglobin has a lower cooperativity and oxygen affinity than most mammalian hemoglobins. In contrast to the usual invariance of cooperativity with pH, a rise in cooperativity with pH is predicted by the allosteric model for low-affinity hemoglobins. Such a pH-dependent cooperativity for cat hemoglobin has been found. 相似文献