Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two lectin fractions (FI and FII) were obtained from seeds of Butea frondosa by affinity chromatography on a sorbent of macroporous glass coupled to the disaccharide alpha-D-GalNAc-(1----3)-beta-D-Gal. Both of these fractions, although different in their sugar specificity, were found on SDS-PAGE to consist of two polypeptide chains of 33 kDa and 35 kDa. In the native state the subunits associated to form a 250 kDa complex, possibly comprising four molecules of the 33 kDa polypeptide and four molecules of the 35 kDa polypeptide. The presence of a faint 70 kDa band when the 250 kDa complex was subjected to SDS-PAGE may indicate the existence of a sequential mechanism of aggregation. N-terminal amino acid sequence analysis revealed extensive homology between these lectins and those of other Leguminosae.
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PMID:Studies on the N-terminal sequences of lectins isolated from the seeds of Butea frondosa. 184 34

Protein profiles of in vivo propagated and in vitro cultivated Treponema pallidum subsp. pallidum (Nichols strain) were analyzed using two-dimensional gel electrophoresis (2D-PAGE). A comparative study between the two protein profiles (as detected by silver stain, Western blotting, and autoradiography) demonstrated two in vitro synthesized polypeptides with approximate molecular masses of 29- and 35 kDa (both with pI 5.62) which were absent in the protein profile of the in vivo propagated T. pallidum. It also was demonstrated that the in vitro cultivated organisms lacked an antigenic polypeptide (as judged by Western blots) of approximate molecular weight 35 kDa (pI 5.34) which was present in the in vivo propagated organisms. To determine the cellular location of these polypeptides, the outer membrane proteins of T. pallidum was extracted with Triton X-114. The extracted proteins were subjected to phase partitioning and the 2D-PAGE protein profiles of the detergent and aqueous phases were compared. The results indicated that in vitro cultivation caused some changes in the cytoplasmic protein profiles of T. pallidum, but no changes were detected in the profiles of the membrane proteins.
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PMID:Identification of T. pallidum polypeptides: a comparative study between the protein profiles of in vitro cultivated and in vivo propagated Treponema pallidum subsp. pallidum by two-dimensional polyacrylamide gel electrophoresis. 193 99

We have examined the apolipoprotein content of the lipoproteins of several marine mammals by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Their apolipoprotein (apo) B-100, apoB-48, and apoA-I migrated to virtually the same position as the comparable human apolipoproteins. In cetaceans (bottlenose dolphins and killer whales), the molecular mass of the apoE was identical to that of human apoE (35 kDa). In contrast, in the lipoproteins of pinnipeds (harbor seals, sea lions, and walrus) there was no protein comparable in size to human apoE; however, there were two proteins in the 40- to 44-kDa range. The protein with the higher apparent molecular weight (44 kDa) was apoA-IV, as determined by NH2-terminal amino acid sequencing. Sequencing of the NH2-terminal 15 amino acids of the lower molecular weight protein (40-42 kDa) revealed no obvious homology with human apoE. However, a human apoE-specific monoclonal antibody, 1D7, bound to the 40- to 42-kDa protein, allowing us to identify that protein as apoE. Sequencing of sea lion apoE cDNA clones demonstrated that sea lion apoE is 311 amino acids in length, 12 residues longer than human apoE. All 12 additional residues are located in the NH2-terminal 31 amino acids, a region that has extremely low homology with the NH2-terminal portion of human apoE. The remainder of the sea lion apoE sequence is 74% homologous to human apoE. The sea lion apoE cDNA was expressed in Chinese hamster ovary (CHO) cells as well as CHO ldlD cells, a cell line that is deficient in O-glycosylation of proteins. The size of the sea lion apoE secreted by these two cell lines, compared with the apoE in sea lion plasma, indicated that the predominant form of apoE in sea lion plasma must be posttranslationally modified. Thus, our studies have demonstrated that the higher apparent molecular weight of pinniped (sea lion) apoE is due to a longer polypeptide chain as well as posttranslational modification of the protein.
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PMID:Lipoproteins in pinnipeds: analysis of a high molecular weight form of apolipoprotein E. 194 Jun 17

Murine T cells synthesize and express a cell-surface glycophospholipid anchored 40 kDa and a secreted water-soluble 39 kDa Qa-2 polypeptide. We have examined the biosynthetic pathways which lead to the production of the membrane-bound and water-soluble isoforms of the Qa-2 molecule. Using the detergent TX-114, both detergent (membrane)-bound and soluble Qa-2 polypeptides can be identified in cell lysates and can be distinguished by charge and molecular weight. Two membrane-bound forms, a 40-kDa Endo H resistant cell-surface form and a 38 kDa-Endo H sensitive form can be identified, both of which can be biosynthetically labeled with 3H-ethanolamine and can be converted to water soluble forms by digestion with a phosphatidylinositol specific phospholipase C. In addition, several water soluble polypeptides at 39, 37, 35 kDa, and a minor species at 33 kDa were identified, none of which radiolabel with 3H-ethanolamine. While the 39-kDa polypeptide was Endo H resistant, the other isoforms were sensitive to Endo H digestion. Pulse chase experiments and molecular weights of the deglycosylated core polypeptides suggest a precursor to product relationship between the intracellular water-soluble species and the mature 39-kDa secreted Qa-2 molecule. This relationship is supported by the observation that murine L cells transfected with the Qa-2 encoding class I gene Q7 fail to express membrane-bound Qa-2 molecules yet synthesize both intracellular water-soluble and secreted Qa-2 molecules. These findings argue for a pathway in which secreted soluble Qa-2 molecules are derived from intracellular precursors.
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PMID:Biosynthesis of glycophospholipid bound and secreted murine class I Qa-2 polypeptides. 196 Dec 2

Liver parenchymal cells continuously extract high amounts of bile acids from portal blood plasma. This uptake process is mediated by a Na+/bile acid cotransport system. A cDNA encoding the rat liver bile acid uptake system has been isolated by expression cloning in Xenopus laevis oocytes. The cloned transporter is strictly sodium-dependent and can be inhibited by various non-bile-acid organic compounds. Sequence analysis of the cDNA revealed an open reading frame of 1086 nucleotides coding for a protein of 362 amino acids (calculated molecular mass 39 kDa) with five possible N-linked glycosylation sites and seven putative transmembrane domains. Translation experiments in vitro and in oocytes indicate that the transporter is indeed glycosylated and that its polypeptide backbone has an apparent molecular mass of 33-35 kDa. Northern blot analysis with the cloned probe revealed crossreactivity with mRNA species from rat kidney and intestine as well as from liver tissues of mouse, guinea pig, rabbit, and man.
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PMID:Functional expression cloning and characterization of the hepatocyte Na+/bile acid cotransport system. 196 29

Our previous study disclosed strong immunostaining of brain tissue in neuronal ceroid lipofuscinosis (NCL) with antibodies against amyloid beta-protein and the presence of 31-kDa polypeptide in the storage material. In the present study, we investigated the immunoreactivity of the NCL brain tissue with anti-serum (anti-GID) raised against a synthetic peptide, based on the amyloid beta-protein precursor, with the 175-186 amino acid sequence. Immunocytochemistry was performed on autopsy brain material collected from 15 NCL cases, and from 8 age-matched normal controls. The results showed strong immunoreactivity of nerve cells in the NCL cases, which according to densitometry was 5 times more intense than in the control group (P less than 0.0001 by Student's t-test). Western blot analysis revealed that in protein fractions of NCL brain homogenates anti-GID recognized the protein band of 35 kDa. Thus our present and previously performed studies supplied for the first time data pointing to abnormal processing of amyloid beta-protein precursor in NCL. Moreover, the accumulation of both 31- and 35-kDa polypeptides that was demonstrated provides further support for postulated defective protein metabolism in this disorder.
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PMID:Altered amyloid beta-protein precursor processing in brains of patients with neuronal ceroid lipofuscinosis. 212 6

The receptor for human urokinase-type plasminogen activator (u-PA) was purified from phorbol 12-myristate 13-acetate-stimulated U937 cells by temperature-induced phase separation of detergent extracts, followed by affinity chromatography with immobilized diisopropyl fluorophosphate-treated u-PA. The purified protein shows a single 55-60 kDa band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and silver staining. It is a heavily glycosylated protein, the deglycosylated polypeptide chain comprising only 35 kDa. The glycosylated protein contains N-acetyl-D-glucosamine and sialic acid, but no N-acetyl-D-galactosamine. Glycosylation is responsible for substantial heterogeneity in the receptor on phorbol ester-stimulated U937 cells, and also for molecular weight variations among various cell lines. The amino acid composition and the NH2-terminal amino acid sequence are reported. The protein has a high content of cysteine residues. The NH2-terminal sequence is not closely related to any known sequence. The identification of the purified and sequenced protein with the human u-PA receptor is based on the following findings: 1) the ability of the purified protein to bind u-PA and its amino-terminal fragment; 2) the identical electrophoretic mobilities observed for cross-linked conjugates, formed between either the purified protein or the u-PA receptor on intact U937 cells and the above ligands; 3) the identity of the apparent molecular weight of the purified protein to that predicted for the u-PA receptor in the same cross-linking studies; 4) the identical extent of glycosylation of the purified protein and of the u-PA receptor in crude membrane fractions, as detected after cross-linking; 5) the ability of antibodies raised against the purified protein to inhibit cellular binding of the amino-terminal fragment of u-PA.
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PMID:The human receptor for urokinase plasminogen activator. NH2-terminal amino acid sequence and glycosylation variants. 215 52

A new, rapid method for purification of inositol(1,4,5)P3 3-kinase in high yield from rat brain is described. Purified enzyme exhibited a polypeptide of Mr = 53,000 on sodium dodecyl sulfate-polyacrylamide gel and a specific activity of 29 mumol/min/mg at 37 degrees C in the absence of calmodulin. Inclusion of calpain inhibitors was critical for obtaining the 53-kDa protein as the major product and 0.1% of the zwitterionic detergent, 3-[(3-cholamidopropyl)dimethylamino]-2-propanesulfonate, was necessary to stabilize enzyme activity. In the absence of calpain inhibitors, the 53-kDa protein degraded progressively during purification and yielded a mixture containing polypeptides of various sizes. Relative intensity of these degradation products on sodium dodecyl sulfate-polyacrylamide gel varied from one preparation to another. However, broad band(s) at the 42-45 kDa region and a band at 35 kDa were always weak, while bands of 53, 51, 40 (sometimes doublets), 33, and 32 KDa were usually strong. The fact that all of these polypeptides including the weak bands of 42-45 and 35 kDa were derived from the 53 kDa form was confirmed by their immunocross-reactivity with monoclonal antibodies to the 53 kDa form. When the 51, 40, and a mixture of the 33 and 32 kDa forms were obtained separately and nearly free from other forms, each of them exhibited catalytic activity. Nevertheless, calmodulin binds to polypeptides larger than 35,000 but not to the 33 and 32 kDa forms. Incubation of the purified 53 kDa form with calpain generated a fragmentation pattern nearly identical to that generated during purification in the absence of calpain inhibitors. Incubation with five other endoproteases produced proteolytic fragments slightly different from those by calpain. However, the general fragmentation patterns generated by the proteases were similar, suggesting that inositol(1,4,5)P3 3-kinase contains several motifs susceptible to a variety of proteases.
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PMID:Purification and properties of D-myo-inositol 1,4,5-trisphosphate 3-kinase from rat brain. Susceptibility to calpain. 216 Sep 80

The characteristics of a rotaviruslike (SBR) virus isolated from striped bass (Morone saxatilis) were examined following purification of viruses from infected cell cultures. Virions had a double-layered capsid of icosahedral symmetry and a diameter of 75 nm. Purified viruses contained five polypeptides ranging in molecular mass from 130 to 35 kDa. None of the structural proteins were glycosylated. Treatment with EDTA did not remove the outer capsid. By using enzymes and a chaotropic agent, it was shown that VP5 was the most external polypeptide. The genome of SBR virus was composed of 11 segments of double-stranded RNA (dsRNA). The electrophoretic pattern of the dsRNA of SBR virus was different from that of reovirus type 1 (Lang) and rotavirus (SA11) dsRNA. The SBR virus was compared with reovirus type 1 and SA11 virus by RNA-RNA blot hybridization. There was no cross-hybridization between any of the genome segments of the SBR, reovirus type 1, or SA11 viruses. Antigenic comparison of SBR virus and SA11 virus by cross-immunoprecipitation and cross-immunofluorescence tests did not show any relationship. These results suggest that SBR virus could represent a new genus within the family Reoviridae.
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PMID:Molecular characterization of a rotaviruslike virus isolated from striped bass (Morone saxatilis). 217 Jun 70

1. Liver plasma membranes originating from the sinusoidal, lateral and canalicular surface domains of hepatocytes were covalently labelled with sulpho-N-hydroxysuccinamide-biotin. After solubilization in Triton X-114, treatment with a phosphatidylinositol-specific phospholipase C (PI-PLC), two-phase partitioning and 125I-streptavidin labelling of the proteins resolved by PAGE, six major polypeptides (molecular masses 110, 85, 70, 55, 38 and 35 kDa) were shown to be anchored in bile canalicular membrane vesicles by a glycosyl-phosphatidylinositol (G-PI) 'tail'. 2. Permeabilized 'early' and 'late' endocytic vesicles isolated from liver were also examined. Two polypeptides (110 and 35 kDa) were shown to be anchored by a G-PI tail in 'late' endocytic vesicles. 3. Analysis of marker enzymes in bile-canalicular vesicles treated with PI-PLC showed that 5'-nucleotidase and alkaline phosphatase, but not leucine aminopeptidase and ecto-Ca2(+)-ATPase activities were released from the membrane. A low release and recovery of alkaline phosphodiesterase activity was noted. The cleavage from the membrane of 5'-nucleotidase as a 70 kDa polypeptide was confirmed by Western blotting using an antibody to this enzyme. 4. Antibodies raised to proteins released from bile-canalicular vesicles by PI-PLC treatment, and purified by partitioning in aqueous and Triton X-114 phases, localized to the bile canaliculi in thin liver sections. Antibodies to proteins not hydrolysed by this treatment stained by immunofluorescence the sinusoidal and canalicular surface regions of hepatocytes. 5. Antibodies generated to proteins cleaved by PI-PLC treatment of canalicular vesicles were shown to identify, by Western blotting, a major 110 kDa polypeptide in these vesicles. Two polypeptides (55 and 38 kDa) were detected in MDCK and HepG-2 cultured cells. 6. Since two of the six G-PI-anchored proteins targeted to the bile-canalicular plasma membrane were also detected in 'late' endocytic vesicles, the results suggest that a junction where exocytic and endocytic traffic routes meet occurs in a 'late' endocytic compartment.
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PMID:Priority targeting of glycosyl-phosphatidylinositol-anchored proteins to the bile-canalicular (apical) plasma membrane of hepatocytes. Involvement of 'late' endosomes. 217 97


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