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211.
The Structure of Calf Liver Cytochrome <Emphasis Type="Italic">b</Emphasis><Subscript>5</Subscript> at 2.8 Å Resolution 总被引:5,自引:0,他引:5
CYTOCHROME b5 is a haem-containing protein in the microsomes of liver tissue. It interacts specifically with a flavo-protein, cytochrome b5 reductase, which catalyses the transfer of electrons from NADH to the haem iron of the cytochrome1. The microsomal cytochrome b5 system has been implicated in fatty acid desaturation reactions2 and a similar system in erythrocytes may catalyse the reduction of methaemoglobin3. Calf liver cytochrome b5, solubilized by pancreatic lipase, has a molecular weight of 11,000 and consists of ninety-three amino-acids in the sequence shown in Fig. 1 (refs. 4 and 5). The haem group is non-covalently bound to the protein and can be removed reversibly by acid acetone treatment6. 相似文献
212.
KOJI NAKANISHI STEVEN BLOBSTEIN MAKOTO FUNAMIZU NOBUO FURUTACHI GEORGE VAN LEAR DEZIDER GRUNBERGER KARL W. LANKS I. BERNARD WEINSTEIN 《Nature: New biology》1971,234(47):107-109
WE wish to report that reconstituted sperm whale myoglobin prepared by the method of Breslow1 (except that pH 2 was found sufficient to remove all the haem) (I) crystallizes2 in a different habit from those prepared by the method of Rossi-Fanelli et al.3 (II) using haemin of Sigma lot 77B-0220 and our own 57Fe photoporphyrin preparation and the native myoglobin (III). Although all three form type A3 monoclinic prisms, the best developed plane is [001] for II and III, it is [100] for I. There seems to be great interest in reconstituted haemoproteins4,5, so it is important that crystallization habit may be a sensitive test for subtle changes in protein structures. 相似文献
213.
Role of the Galactose Binding Protein in Chemotaxis of <Emphasis Type="Italic">Escherichia coli</Emphasis> toward Galactose 总被引:51,自引:0,他引:51
The galactose binding protein is the part of the galactose chemoreceptor which recognizes the attractants galactose, glucose and a number of structurally related chemicals. 相似文献
214.
Ribosomes,G-factor and Siomycin 总被引:13,自引:0,他引:13
G-factor interacts with the 50S ribo-somal subunit at a site which is distinct from the peptidyl transferase centre and which is inactivated by siomycin. 相似文献
215.
Passive Haemagglutination Test for Anti-rhinovirus Antibodies 总被引:2,自引:0,他引:2
W. PAGE FAULK G. N. VYAS C. A. PHILLIPS H. HUGH FUDENBERG K. CHISM 《Nature: New biology》1971,231(21):101-104
The use of chromic chloride as a coupling reagent has made it possible to coat red cells with rhinovirus protein. This is shown by immunofluorescence, electron microscopy and immunocolloidal experiments. 相似文献
216.
RICHARD L. SIMMONS MARTIN L. LIPSCHULTZ ANGELYN RIOS PRASANTA K. RAY 《Nature: New biology》1971,231(21):111-112
DURING outbred pregnancy the mother is exposed to genetically foreign tissue because the offspring inherits transplantation antigens from the father. The survival of the foetus is ensured by the intervention of the trophoblast which does not express transplantation antigens between mother and foetus: mouse trophoblast is not rejected even when transplanted into immune recipients1,3. The mechanism of this failure to express histocompatibility antigens is not understood1–4, but Kirby et al. have suggested that the extracellular fibrinoid surrounding trophoblast cells is involved5,6. Currie has suggested that the thick sialomucinous glycocalyx of the trophoblast cell might “mask” the histocompatibility antigens on the trophoblast7,8 and has demonstrated that neuraminidase unmasked these antigens8. Our experiments, however, show that trophoblast incubated with neuraminidase cannot sensitize allogeneic mice to donor histocompatibility antigens. Furthermore, pretreatment of trophoblastic implants with neuraminidase did not interfere with their proliferation and growth in highly immune allogeneic recipients. 相似文献
217.
Constant Production of Type C Virus Particles in a Continuous Tissue Culture derived from Pleural Effusion Cells of a Lymphoma Patient 总被引:5,自引:0,他引:5
ELIZABETH S. PRIORI LEON DMOCHOWSKI BROOKS MYERS J. R. WILBUR 《Nature: New biology》1971,232(28):61-62
PARTICLES resembling viruses were first observed in organs of mice with spontaneous leukaemia and in thin sections of a biopsy specimen from a lymph node of a patient with acute lymphocytic leukaemia by Dmochowski and Grey1. They also found them in some biopsy specimens of lymph nodes and bone marrows before and after growth in tissue culture2,3,8. Recent reports have described the presence of type C virus particles in other human tumours including liposarcoma4, osteosarcoma5,6, giant cell tumour9, rhabdomyosarcoma (unpublished results of L. D. and E. S. P.) and breast carcinoma7. 相似文献
218.
Antigenic Heterogeneity of Human IgD Immunoglobulins 总被引:3,自引:0,他引:3
SUBCLASSES of the three major classes of human immunoglobulins, IgG, IgA and IgM, are recognized: four of IgG are well defined1,2 and at least two of IgA3–5 and two of IgM6,7 have been demonstrated. This communication presents evidence for the existence of an antigenic heterogeneity in the heavy chains of IgD, which may also be indicative of subclasses within this class of immunoglobulin. 相似文献
219.
Coexistence of Intraspecies and Interspecies Specific Antigenic Determinants on the Major Structural Polypeptide of Mammalian C-type Viruses 总被引:41,自引:0,他引:41
THE report of a shared viral antigen (termed gs-3) among mammalian C-type viruses from four species1, extending an earlier report of cross reactivity between mouse and cat viral antigens2, has far reaching implications in the search for human cancer viruses or their gene products. The report is confirmed both by the data presented here and also by the data obtained by another laboratory3. Our gel diffusion assays using various selected sera against mouse, hamster and cat crude and purified C-type viral antigens indicate that the cross reactive antigenic determinants are specifically present on the major structural polypeptide of C-type viruses. The polypeptide also carries species specific determinants. These conclusions are drawn from complement fixation and gel diffusion tests using six types of antisera (either individual sera or pools) prepared as described in Table 1. 相似文献
220.
Binding of Radioactively Labelled Concanavalin A and Wheat Germ Agglutinin to Normal and Virus-transformed Cells 总被引:32,自引:0,他引:32
VARIOUS substances isolated from plants cause animal cells to clump. Several of these lectins1 preferentially agglutinate cells which have been transformed spontaneously or by chemicals or viruses2–7. The best known lectins of this class are concanavalin A (Con A) isolated from jack beans8 and wheat germ agglutinin4, which seem to bind to carbohydrate groups on the cell surface. The determinants recognized by the lectins seem to be N-acetyl-D-glucosamine for WGA4 and probably α-methyl-D-glucopyranoside for Con A6. 相似文献