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

Poly-L-lysine, a synthetic cationic polypeptide known for its ability to bind to cell membranes, was found to induce differentiation of Friend leukemia cells "in vitro". Studies were extended to the same "in vitro" model, in order to examine the therapeutic potential of this new differentiating agent. The i.p. administration of the polymer (Mw 2700) at the maximal tolerated dose resulted in major alterations of disease-related parameters. In particular, a multiple treatment schedule on the advanced disease resulted in a successful reduction of target organ weight and peripheral white blood cell count and appreciable differentiation of spleen and bone marrow cells. Apparently, the effects of poly-L-lysine were superior to those produced by N-methyl-acetamide, a potent inducer of differentiation "in vitro".
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PMID:In vitro and in vivo studies of poly-L-lysine as inducer of Friend leukemic cells differentiation. 347 55

Poly- and monoclonal antibodies have been prepared against the cytoplasmic domain (43 kDa) and the 17-, 20-, and 35-kDa fragments of the membrane-spanning domain of the human erythrocyte anion exchanger, band 3. The antibodies were used to localize and further characterize analogues of band 3 in the human kidney. We report here that the basolateral membrane of intercalated cells of the connecting tubules and collecting ducts contains an analogue of band 3 that appears to be highly homologous to the erythrocyte anion exchanger. This band 3-like protein is probably important for reabsorption of bicarbonate in the collecting duct system and thus for acidification of the forming urine. The band 3-like protein of the intercalated cells contain immunoreactive sites of both the cytoplasmic domain and the three major fragments of the membrane-spanning domain of erythrocyte band 3. Although no immunological differences were detected between the membrane-spanning domains of band 3 in erythrocytes and intercalated cells, there are at least three sites along the cytoplasmic domain of kidney band 3 that differ from erythrocyte band 3 in either amino acid composition or posttranslational modifications. The main kidney analogue of band 3 that contains epitopes of the cytoplasmic domain as well as the 17- and 35-kDa membrane-spanning domain of erythroid band 3 is a polypeptide with an apparent molecular mass of 100-110 kDa. Further immunoreactive polypeptides at approximately 180, approximately 140, approximately 38, approximately 25-30 kDa that were detected at lower stringency and higher sensitivity of the immunoblotting procedure may be members of a multigene family that encodes a series of related proteins.
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PMID:Immunochemical characterization of a band 3-like anion exchanger in collecting duct of human kidney. 361 86

The architecture of human complement component C9 and poly(C9) was investigated by transmission electron microscopy. Monomeric native C9 (Mr = 66,000) exhibits an ellipsoid appearance (70 X 50 A) with a crevice visible on one face. C9 polymerizes spontaneously to form hollow tubular structures consisting of 12-16 monomeric subunits. Poly(C9) is a cylinder (150 A-outer diameters and 90 A-inner diameter) rimmed by a torus (46-A thick) on one end. Electron micrographs of poly(C9) indicate that the torus is formed by radial strands of polypeptide. Each subunit of poly(C9) is apparently tilted relative to the central axis of the cylindrical structure. C9 can be cleaved by alpha-thrombin into two single-chain polypeptide fragments: C9a (Mr = 28,000) and C9b (Mr = 38,000), which are the amino- and carboxyl-terminal segments of the protein, respectively. The cleaved form of the protein, C9a,b, can be induced to polymerize under suitable conditions to form sodium dodecyl sulfate-resistant poly(C9), indicating that the resistance of poly(C9) to denaturation is a collective feature of both C9a and C9b. The C9a and C9b polypeptide regions have been mapped on poly(C9) by immunoelectron microscopy. Determinants for the C9a region were observed about the torus, base, and on the midsection of the poly(C9) cylinder. C9b epitopes are concentrated predominantly about the torus and base, but were rarely observed on the midsection of poly(C9). Thus, the C9a and C9b segments of the C9 polypeptide are not clearly segregated in poly(C9). The locations of oligosaccharide units on poly(C9) were visualized by electron microscopy after labeling of the complex with concanavalin A bound to colloidal gold. The oligosaccharide positions were found on the periphery of the torus and base. In summary, C9 appears to be a single-domain protein. Polymerization involves a major rearrangement. To form a subunit of poly(C9) the polypeptide chain must form at least one major fold parallel to the central axis of the tubule.
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PMID:The architecture of complement component C9 and poly(C9). 405 1

In the yeast Cryptococcus albidus, the utilization of xylan as compared to xylose requires at least an inducible endoxylanase enzyme, secreted in the culture medium. The endoxylanase induction was monitored by immunoprecipitation of in vivo and in vitro synthesized products. The mature endoxylanase is a highly glycosylated enzyme with an apparent molecular weight of 48 000. Upon chemical deglycosylation with trifluoromethanesulfonic acid, the molecular weight was reduced to 40 000. Addition of tunicamycin to the culture medium resulted in the synthesis of a modified polypeptide having a molecular weight of 40 000. Poly(A)-containing RNA isolated from the yeast was translated in the rabbit reticulocyte protein-synthesizing system. The appearance of a translatable xylanase mRNA was observed in xylan-grown cells but not in xylose-grown cells. The polypeptide identified as xylanase had a molecular weight of 44 000. This suggests that the xylanase is synthesized as a precursor, containing a peptide signal sequence of 35 residues.
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PMID:Molecular expression of xylanase gene in Cryptococcus albidus. 407 44

Extracts of wheat germ are capable of synthesizing the major capsid protein of simian virus 40. Poly(A)-containing RNA from BS-C-1 cells infected with simian virus 40 directed the synthesis of a novel polypeptide that migrates in polyacrylamide gels together with the major capsid polypeptide of simian virus 40, VP-1. The patterns of the major tryptic peptides of purified VP-1 and the novel polypeptide synthesized in vitro were identical after two-dimensional paper electrophoresis. The novel polypeptide was not synthesized in response to poly(A)-rich RNA from uninfected cells or from virus-infected cells treated with cytosine arabinoside. Messenger RNA from infected cells purified by selective hybridization to DNA of simian virus 40 directs the synthesis of a major polypeptide of electrophoretic mobility similar to that of VP-1 of simian virus 40. This approach should prove useful in identifying additional products specified by DNA tumor viruses.
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PMID:Cell-free translation of messenger RNA of simian virus 40: synthesis of the major capsid protein. 436 Sep 38

This report details the procedural requirements for preparing cell-free extracts of yeast rich in polyribosomes. This enabled us to demonstrate the occurrence of polyribosomes in yeast, to show their role in protein synthesis, and to devise methods for their resolution and isolation. When certain precautions are met (the use of log phase cells, rapidly halting cell growth, gentle methods of disruption, sedimentation through exponential density gradients, etc.), individual polyribosome size classes ranging up to the heptosome can be fractionated and separated from their nearest neighbors. Larger size classes are resolved partially among themselves, free of smaller polyribosomes. This was confirmed by extensive electron micrographic studies of material from the various fractions obtained upon density gradient centrifugation of yeast extracts. Modifications of the gradients and procedure should allow fractionation and isolation of the larger polyribosomes, including those containing polycistronic messages. Yeast polyribosomes are disaggregated to single ribosomes by longer term grinding, cell disruption by the French pressure cell, the Hughes press, or by incubation with dilute RNAse. Yeast polyribosomes are active in the incorporation of amino acids into polypeptide; the single ribosomes exhibit only slight activity. The latter activity is probably due to the presence of a small fraction of monosomes still containing mRNA. Poly-U stimulates amino acid incorporation only in the single ribosomes.
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PMID:Occurrence, isolation, and characterization of polyribosomes in yeast. 603 41

Poly(A)mRNA was isolated from the endoplasmic reticulum (ER) of male BALB/c mice and used as the template for cDNA synthesis. Double-stranded (ds) cDNA was cloned in a bacterial plasmid and 21 clones were selected for further study. Six clones have been identified by hybrid selection of mRNA, translation of the mRNA in a template-dependent system, polyacrylamide gel electrophoresis and specific immunoprecipitation. Four code for the major urinary protein of the mouse (MUP), one for serum albumin and one for alpha 1-antitrypsin. A seventh codes for an unidentified polypeptide with Mr = 27000. Initial-rate hybridisation kinetics of immobilised cloned sequences with end-labelled mRNA showed that serum albumin mRNA is most abundant in the population of mRNA species present in the endoplasmic reticulum fraction of female BALB/c liver. MUP mRNA is also very abundant. The alpha 1-antitrypsin mRNA and the mRNA specifying the 27000-dalton protein are about 5 times less abundant than serum albumin mRNA on a molar basis.
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PMID:Molecular cloning of cDNA sequences transcribed from mouse liver endoplasmic reticulum poly(A)mRNA. 611 4

Rat hepatoma cells that have undergone stepwise selection in increasing concentrations of pyrazofurin have coordinately increased levels of both orotate phosphoribosyltransferase (EC 2.4.2.10) and orotidine-5'-phosphate decarboxylase (EC 4.1.1.23) activity. These two activities catalyze the conversion of orotic acid to UMP in de novo pyrimidine biosynthesis. Cells selected in 50 microM pyrazofurin have over 40 times the wild type level for both activities. A single polypeptide of approximately 55,000 daltons is increased in the resistant cells in amounts corresponding to the increase in the two activities. Resistant cell lines that are grown for extended periods in the absence of pyrazofurin are unstable, losing their elevated levels of both enzyme activities and the increased specific protein. Antibody prepared against a purified protein containing both enzyme activities binds specifically to this increased protein. These results corroborate other evidence indicating the two enzyme activities are contained within a single polypeptide called UMP synthase. Poly(A+) mRNA isolated from wild type and resistant lines was analyzed by in vitro translation for production of UMP synthase protein. Immunoprecipitation of the translation products shows the resistant cells have a 17-fold increase in translatable mRNA activity coding for UMP synthase. The synthase accounts for 0.24% of the total in vitro translation products synthesized with poly(A+) mRNA from the pyrazofurin-resistant cells as opposed to 0.014% with wild type mRNA. A cloned UMP synthase cDNA sequence hybridizes strongly to a 1.8-kilobase mRNA in the resistant cells. This mRNA is only barely detectable in equivalent preparations from wild type cells. Quantitation of the mRNA by dot hybridization techniques indicates a 16-fold increase in UMP synthase mRNA in the resistant cells. Although this increase in mRNA for UMP synthase could explain most of the increased protein, it is not sufficient to totally account for the 40-fold increase in UMP synthase.
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PMID:Increased levels of UMP synthase protein and mRNA in pyrazofurin-resistant rat hepatoma cells. 613 25

Poly(A)+RNA from phenol-extracted rat liver polysomes was translated in a heterologous cell-free system derived from wheat germ. The RNA stimulated the incorporation of [35S]methionine into proteins 20- to 30-fold. The labeled translation products were incubated with an antiserum against cytochrome c oxidase. After binding of the antigen x immunoglobulin complex to and elution from protein A-Sepharose and sodium dodecyl sulfate (SDS)-polyacrylamide step gel electrophoresis, autoradiography was carried out. Mainly one major protein with an apparent molecular weight of 19,500 was visualized. When the unlabeled individual cytochrome c oxidase subunits IV, V, VI, or VII, isolated from preparative SDS-polyacrylamide gels, were added to the translation mixture, it was found that only subunit IV could compete with the in vitro-synthesized protein of 19.5 kilodaltons in respect to the binding to the cytochrome c oxidase antiserum. The in vitro-synthesized product was 3,000 daltons larger than the cytochrome c oxidase subunit polypeptide IV. It is concluded that the subunit IV is synthesized as a precursor. Evidence for the precursor form was obtained from translation experiments with [35S]methionine bound to a specific initiator tRNA which led to a radioactively labeled product of identical electrophoretic mobility as the 19.5 kilodalton protein. Furthermore, two dimensional tryptic fingerprints of subunit IV and its precursor show a high degree of similarity.
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PMID:Synthesis of a larger precursor for the subunit IV of rat liver cytochrome c oxidase in a cell-free wheat germ system. 615 37

Poly(A)-RNAs enriched for glycinin coding sequences were injected into frog oocytes and translated in the presence of either [3H]leucine or [3H]isoleucine. Sodium dodecyl sulfate electrophoresis indicated that radioactive proteins similar in size to the authentic acidic and basic polypeptide components of glycinin were not present among the glycinin-related proteins synthesized. Instead, high molecular weight precursors (Mr = 58,000-67,000) were immunoprecipitated. Unlike disulfide-linked native glycinin complexes which were cleaved by disulfide reduction, products purified from either rabbit reticulocyte lysate or oocyte translation systems were insensitive to reducing agents. The glycinin-related proteins synthesized in the oocyte were 1000 to 2000 daltons smaller than those synthesized in the reticulocyte lysate system. This result, which suggested that the oocyte system had removed NH2-terminal leader sequences of the preglycinin polypeptides, was confirmed by NH2-terminal sequence analysis of proteins synthesized in oocytes. Radioactive label was found exactly at the positions predicted by the NH2-terminal sequences of the acidic polypeptide component of native glycinin. Glycinin precursors, therefore, have an NH2-terminal leader sequence followed by the acidic peptide component and then the basic polypeptide component, joined in peptide linkage.
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PMID:Structural characterization of the glycinin precursors. 617 36


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