UNIPROT:Q07644 - FACTA Search

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Query: UNIPROT:Q07644 (polypeptide)
72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The amino acid composition and NH2-terminal amino acid sequence of barley nuclease (EC 3.1.30.2) were determined. The amino acid composition is similar to that of mung bean nuclease, and therefore the biochemical properties of barley nuclease were characterized and compared with those of mung bean and other plant nucleases. The 3'-nucleotidase activity of barley nuclease is greater for purine than for pyrimidine ribonucleotides. The enzyme has little activity towards ribonucleoside 2' and 5'-monophosphates, and deoxyribonucleoside 3' and 5'-monophosphates, and is also inactive towards the 3'-phosphoester linkage of nucleoside cyclic 2',3' and 3',5'-monophosphates. The enzyme hydrolyzes dinucleoside monophosphates, showing strong preference for purine nucleosides as the 5' residues. Barley nuclease shows significant base preference for homoribonucleic acids, catalyzing the hydrolysis of polycytidylic acid greater than polyuridylic acid greater than polyadenylic acid much greater than polyguanylic acid. The enzyme also has preference for single-stranded nucleic acids. Hydrolysis of nucleic acids is primarily endonucleolytic, whereas the products of digestion possess 5'-phosphomonoester groups. Nuclease activity is inhibited by ethylenediaminetetraacetic acid and zinc is required for reactivation. Secretion of nuclease from barley aleurone layers is dependent on the hormone gibberellic acid [Brown, P.H. and Ho, T.-h. D. (1986) Plant Physiol. 82, 801-806]. Consistent with these results, gibberellic acid induces up to an eight-fold increase in the de novo synthesis of nuclease in aleurone layers. The secreted enzyme is a glycoprotein having an apparent molecular mass of 35 kDa. It consists of a single polypeptide having an asparagine-linked, high-mannose oligosaccharide. The protein portion of the molecule has a molecular mass of 33 kDa.
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PMID:Biochemical properties and hormonal regulation of barley nuclease. 282 11

Carbonic anhydrase (CA) of Chlamydomonas reinhardtii is a glycoprotein of 35 kDa which is localized outside the plasma membrane. The activity of CA was increased when the CO2 concentration during photoautotrophic growth was decreased to air level. After decreasing the CO2 concentration from 4% to 0.04%, several polypeptides including CA were induced continuously or transiently. To investigate the biosynthesis and intracellular processing of CA, the cells of wall-less mutant CW-15, which secretes CA into the culture medium, were pulse-labeled with radioactive arginine, chased, and radioactive proteins were immunoprecipitated with anti-CA serum. A 42-kDa polypeptide with isoelectric point (pI) of 7.1-7.3 was first synthesized. Within 5 min the molecular mass of this polypeptide was decreased to 35 kDa and it was then secreted into the culture medium within 30 min. This indicates that the former is the precursor form and the latter the mature form of CA. The primary translation product from poly(A)-rich RNA in a cell-free reticulocyte lysate system from a rabbit was a 38-kDa polypeptide. This was cotranslationally converted into the 42-kDa precursor in vitro in the presence of dog pancreatic microsomal membranes. As the 42-kDa precursor had a high affinity to concanavalin A, it was assumed to have a high-mannose-type oligosaccharide. The mature enzyme had a pI of 6.1-6.2 and was composed of more than two isoforms, which had a complex-type oligosaccharide with low affinity to concanavalin A. Chemical deglycosylation of the mature enzyme by trifluoromethanesulfonic acid indicated that the molecular mass of the polypeptide moiety was 32 kDa and the difference between this and the primary translation product suggests that cleavage of the polypeptide occurs during its biosynthesis.
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PMID:Biosynthesis and intracellular processing of carbonic anhydrase in Chlamydomonas reinhardtii. 287 27

Transcription factor IIIA (TFIIIA) was purified from cytoplasmic extracts of HeLa cells by developing a simple and efficient procedure employing phosphocellulose under widely differing ionic conditions followed by affinity chromatography on immobilized human 5 S genes. This procedure yielded a fraction containing human TFIIIA activity and a protein of 35 kDa as its major component. Moreover, we succeeded in renaturing the activity of human transcription factor IIIA (hTFIIIA) isolated after preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and in identifying a polypeptide of 35 kDa with the transcription activity. This value differs from that reported for Xenopus TFIIIA. It could be demonstrated by footprinting analyses that hTFIIIA specifically binds to the internal control region of the human 5 S rRNA gene. The limits of protection slightly differ at the 3' border of the internal control region from those imprinted by Xenopus TFIIIA on the same gene. Comparative footprint analyses of hTFIIIA on the human and frog somatic 5 S rRNA gene, measured in titration, competition, and salt-stability experiments, demonstrated a higher affinity of the human factor to the homologous gene. These results, together with the difference in molecular mass of these functionally analogous proteins, reemphasize the importance of homologous systems for the analysis of mechanisms involved in gene regulation.
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PMID:Purification of human transcription factor IIIA and its interaction with a chemically synthesized gene encoding human 5 S rRNA. 291 80

A cytoplasmic particle displaying properties in common with a structure present in duck erythroblasts, termed the prosome, has been isolated from eggs and embryos of two species of sea urchin. This particle was partially purified by sedimentation in sucrose gradients containing 0.5 M KCl, and some of its physical properties and its behavior during early development were determined. The prosome sediments between 16 and 19 S and has a buoyant density of 1.30 g/cm3 in Cs2SO4 gradients. Biochemically, the particle is characterized as 20-25 polypeptides of molecular size 24-35 kDa with about 10 small RNAs. A monoclonal antibody directed against the 27-kDa protein of duck erythroblast prosome recognizes a 27-kDa protein of the sea urchin prosome. We have used this protein, as representative of the prosome, to immunologically determine the level and the subcellular localization of the particle during development. Immunoblotting and cellular fractionation studies show that the 27-kDa prosome polypeptide is present almost entirely in the postribosomal supernatant of unfertilized egg lysates. After fertilization and during early development, the total amount of 27-kDa protein per embryo remains constant, but the amount in the postribosomal supernatant decreases; there is a concomitant increase in the level of the 27-kDa protein in a rapidly sedimenting, particulate fraction containing nuclei. Immunofluorescence studies further show that the 27-kDa protein is located mainly in the cytoplasm of eggs and two-cell embryos. The subcellular location of the prosome, therefore, appears to change during development. In vivo labeling experiments have failed to detect the synthesis of either the prosome proteins or RNAs in eggs and embryos up to 48 hr of development, suggesting that this cytoplasmic particle is not synthesized de novo in early embryogenesis and thus is metabolically stable. The prosome is thus a normal cellular constituent of the sea urchin and is most likely synthesized during oogenesis and stored in the unfertilized egg.
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PMID:Sea urchin prosome: characterization and changes during development. 295 33

The EDTA-extractable protein (EEP) is a major extrinsic protein of lens membrane. The 35 kilodalton (kDa) polypeptide of the EEP cross-reacted to antibody prepared against calpactin I, a substrate for the src protein and an inhibitor of phospholipase A2. Calpactin I is also thought to play a structural role in linking cytoskeleton to membrane. The 35 kDa protein in bovine lens contained phosphotyrosine residues that can be detected by affinity purified antibody to this moiety. Although there is some microheterogeneity of EEP using two dimensional gel electrophoresis, at least one of the chick polypeptides, immunoreactive for calpactin I, can be phosphorylated in whole lens culture. These results suggest a regulatory function for the EEP in lens.
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PMID:Identification of the EDTA-extractable protein in lens as calpactin I. 295 57

A 5S-rRNA-containing ribonucleoprotein was purified to homogeneity from a rabbit muscle extract through its affinity to phosphofructokinase-1 and then structurally characterized. This RNP was compared to the 5S-rRNA-containing ribonucleoprotein extracted from rabbit liver ribosomal 60S subunits with EDTA. Analytical gel filtration revealed a molecular mass of 70-80 kDa for both complexes. Gel electrophoresis of the ribosomal complex revealed three protein components, one migrating as a band of 35 kDa and two other small polypeptides of apparently 16.5 kDa and 17.5 kDa. In the sarcoplasmic RNP these small polypeptides were absent. However, besides a major component of 35 kDa, up to five slightly larger and smaller species of 31.5-36.5 kDa were detected. Despite this heterogeneity, only one N-terminal amino acid sequence was obtained for the isolated sarcoplasmic protein, suggesting a C-terminal heterogeneity of one single polypeptide. Within the first 46 amino acid residues no difference between the sequences of the isolated 35-kDa components of sarcoplasmic and ribosomal complexes was found. Homology criteria indicated that this component belongs to the ribosomal protein L5 family. The RNA was identified by complete enzymatic sequencing as 5S rRNA; it was also identical in both complexes and is strongly homologous to 5S rRNA of man. Both L5-5S-RNA complexes could be resolved by hydroxyapatite chromatography into three species still consisting of both protein and RNA. 5'-Terminal dephosphorylation experiments showed that this heterogeneity is exclusively due to the differing number (1-3) of 5'-terminal phosphates. The two additional low-molecular-mass proteins were stably associated to the ribosomal RNP at high salt concentrations in a stoichiometry of about 2:1. They were identified as the acidic phosphoproteins P2/P3 by N-terminal sequencing. High phosphate concentrations facilitated their dissociation from the L5-5S-RNA complex. For the sarcoplasmic L5-5S-RNA complex a hitherto unknown interaction with phosphofructokinase-1, affecting the enzymatic properties, was demonstrated.
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PMID:5S-rRNA-containing ribonucleoproteins from rabbit muscle and liver. Complex and partial primary structures. 296 May 23

Immature double negative (DN) CD4-8- thymocytes expressing the CD3 molecular complex can be subdivided into two distinct subsets based on expression of the B2A2 antigen. Thus, B2A2+ CD3+ DN thymocytes express CD3-associated 35 kDa and 45 kDa polypeptide chains characteristic of a gamma/delta T cell receptor, whereas B2A2- DN thymocytes express predominantly 38 to 43 kDa CD3-associated structures typical of alpha/beta TCR. At the mRNA level, B2A2+ DN thymocytes express full length gamma and delta transcripts but no alpha message and only short (1 kb) B transcripts. In contrast, the B2A2- DN subset expresses full length alpha and beta transcripts and minimal levels of delta transcripts. Interestingly, B2A2- DN thymocytes, unlike mature T cells, also express abundant levels of full length TCR gamma mRNA, perhaps suggesting that these cells represent an early stage after divergence of the gamma/delta and alpha/beta T cell lineages.
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PMID:CD3-associated alpha/beta and gamma/delta heterodimeric receptors are expressed by distinct populations of CD4- CD8- thymocytes. 296 83

The low molecular weight polypeptide required for energy-dependent proteolysis, ubiquitin, is rapidly inactivated by 100,000 X g supernatants of rabbit liver extracts. Ubiquitin inactivation results from limited proteolysis by an endogenous contaminating lysosomal thiol protease having trypsin-like specificity. Evidence for this includes a pH optimum of 5.0 for the first order constant of ubiquitin inactivation and observation that inactivation is inhibited by EDTA, o-phenanthroline, iodoacetamide, p-chloromercuribenzoic acid, phenylmethylsulfonyl fluoride, N alpha-p-tosyl-L-lysine chloromethyl ketone, leupeptin, soybean trypsin inhibitor, and aprotinin. Metals stimulate but are not required for ubiquitin inactivation with the effect apparently mediated by a low molecular weight heat-labile component of crude extracts. When this heat-labile component is removed by gel exclusion chromatography a number of metals inhibit ubiquitin inactivation. In the presence of excess dithiothreitol, inhibition is relatively specific for Zn(II). Inhibition by Zn(II) is specifically overcome competitively by Cd(II) or by a concentration of ubiquitin in excess of Zn(II). The responsible cathepsin possesses a molecular mass of 35 kDa by gel exclusion chromatography and shows marked thermal lability at neutral pH but stability at acid pH. Proteolytic inactivation of ubiquitin results from limited cleavage of the carboxyl-terminal glycine dipeptide required for isopeptide bond formation and is supported by data on isoelectric point changes on subsequent digestion with carboxypeptidase B and by direct amino acid analysis. When the responsible cathepsin is inactivated, liver extracts display ATP,ubiquitin-dependent proteolysis that cannot be ascribed to contaminating erythrocytes. Thus the previous inability to demonstrate energy-dependent proteolysis in liver extracts is accounted for by the artifactual inactivation of ubiquitin.
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PMID:The inactivation of ubiquitin accounts for the inability to demonstrate ATP, ubiquitin-dependent proteolysis in liver extracts. 298 63

Red clover necrotic mosaic virus, a member of the dianthovirus group, is characterized by a genome composed of two nonhomologous single-stranded RNAs of approximately 4.0 (RNA-1) and 1.4 kb (RNA-2). The complete nucleotide sequence of the RNA-2 has been determined. RNA-2 is 1448 nucleotides in length with a 5' terminal m7G cap and no 3' terminal poly-A tail or 5' terminal VPg. An open reading frame beginning at the first initiation codon at nucleotide 80 and ending at nucleotide 1030 has been identified which can encode a polypeptide of 35 kDa. RNA-2 directs the synthesis of a 35 kDa polypeptide in vitro. SP6 and T7 transcripts from full length RNA-2 cDNA clones directed the synthesis of a polypeptide with the same electrophoretic mobility as the polypeptide directed from authentic RNA-2. Clones with various 3' terminal deletions both outside and within the 35 kDa open reading frame were transcribed and translated in vitro to define the limits of the 35 kDa open reading frame. A second, small open reading frame capable of encoding a polypeptide of 4.9 kDa was also indicated from the sequence; however, there was no evidence for a protein product of that size. RNA-2 is presumed to be monocistronic and encode a cell-to-cell movement function. A small but significant amino acid sequence homology was observed with the brome mosaic virus RNA-3a polypeptide.
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PMID:The nucleotide sequence and gene organization of red clover necrotic mosaic virus RNA-2. 304 82

We have identified a component of about 35 kDa (pp35), present in human placental membrane preparations, that is a substrate for epidermal growth factor (urogastrone) [EGF(Uro)]-mediated phosphorylation. The EGF(Uro)-stimulated phosphorylation of pp35 was calcium-dependent and was markedly enhanced in membranes prepared in the presence (but not in the absence) of calcium. The phosphate incorporated into pp35 in the presence of EGF(Uro) was alkali-stable and was present as O4-phosphotyrosine. Under identical conditions, insulin did not stimulate pp35 phosphorylation. Either in its native or in its phosphorylated form, pp35 could be released from the membranes in the presence of calcium-chelating agents (EDTA/EGTA); and EGF(Uro)-stimulated phosphorylation was reconstituted by adding back EDTA/EGTA eluates to EDTA/EGTA-washed membranes in the presence of calcium. The properties of pp35 were similar if not identical to those of beta-35, a 35-kDa polypeptide similar to the beta subunit of the guanine nucleotide-binding oligomers that stimulate (Gs) or inhibit (Gi) the adenylate cyclase system. As with pp35, EGF(Uro)-stimulated phosphorylation of isolated rabbit liver beta-35 was observed in a reconstituted system using either EDTA/EGTA-washed placental membranes or solubilized EGF(Uro) receptor immobilized on concanavalin A-agarose. In contrast, the addition of beta subunits derived from rabbit liver Gi or bovine transducin did not result in phosphorylation of a 35-kDa substrate in the reconstituted system. Further, a 35-kDa protein released from placental membranes crossreacted with an anti-transducin antibody that can recognize the beta subunit isolated from a variety of sources. We conclude that the human placental pp35 substrate likely represents the placental equivalent of the beta-35 protein. Our data point to a possible link between those receptors involved in growth-factor action and the regulatory systems that utilize GTP-binding proteins as transducing elements.
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PMID:Epidermal growth factor (urogastrone)-mediated phosphorylation of a 35-kDa substrate in human placental membranes: relationship to the beta subunit of the guanine nucleotide regulatory complex. 307 7

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