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)

Previous studies have shown that mature arylsulfatase B purified from human sources is composed of two non-identical chains with apparent molecular masses of 43 kDa and 8 kDa. Arylsulfatase B purified from human placenta in the present study, however, included another 7 kDa component that could be detected only by carbohydrate staining on reducing SDS-PAGE employing the Tris-Tricine system. The 43 kDa and 7 kDa components contained a carbohydrate moiety, but the 8 kDa one did not, as demonstrated by periodic acid-Schiff staining, Con-A lectin blotting, endo-glycosidase treatment and in vitro phosphorylation by UDP-N-acetylglucosamine: lysosomal enzyme N-acetylglucosamine 1-phosphotransferase. The purified arylsulfatase B migrated as a single polypeptide of 58 kDa on non-reducing SDS-PAGE, indicating that the three chains are linked by disulfide bonds. In order to determine the origin of the components, N-terminal sequencing of the isolated polypeptides was performed. As a result, the 43, 7 and 8 kDa components were found to commence with Ala-41, Ala-424 and Asp-466, respectively. These results suggest that after removal of the signal peptide, human arylsulfatase B undergoes proteolytic processing on at least two sites during maturation.
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PMID:Components and proteolytic processing sites of arylsulfatase B from human placenta. 139 Sep 29

The gene PHO5 coding for one of the repressible acid phosphatases of the yeast Saccharomyces cerevisiae has been expressed at high efficiency in the baby hamster kidney (BHK) cell line. The expression vector was constructed from PHO5 driven by the human beta-actin promoter and was transfected into BHK cells by the calcium phosphate method. The recombinant APase (r-APase) which was secreted in active form from the cells was estimated by SDS/polyacrylamide gel electrophoresis to have molecular mass M(r) = 62,000, indicating substitution of the polypeptide moiety by 2-3 asparagine-linked glycans. Analysis by sequential lectin affinity chromatography of glycopeptides obtained from r-APase with Pronase showed that the glycans are predominantly of the 2.2.4 triantennary and tetraantennary complex-type. These data suggest that the extensive glycosylation of yeast APase, which contains eight polymannose substituents, is not essential for secretion and expression of enzymatic activity of the transfected gene product.
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PMID:Expression, glycosylation and secretion of yeast acid phosphatase in hamster BHK cells. 139 64

To investigate the role of cilia in mating interactions of Tetrahymena thermophila, ciliary membrane-rich fractions were isolated from two wild-type strains, a non-discharge mucocyst mutant which possesses mating behavior similar to wild-type, and a mating mutant which is able to costimulate cells of complementary mating type but cannot enter into pair formation. In each case, proteins from the ciliary membrane-rich fractions of starved, mating-competent ("initiated") cells were compared with those from non-starved, mating-incompetent ("non-initiated") cells, by gel electrophoresis and lectin blotting. In stained gels, a 43 kDa polypeptide was reduced or absent in initiated cells but present in non-initiated cells, in all strains. In silver-stained gels, a 25 kDa polypeptide was present in all strains, both initiated and non-initiated. In blots probed with Con A-peroxidase, a 25 kDa glycoprotein was present in ciliary membrane fractions from non-initiated cells and absent in membranes of initiated cells of the two wild-type strains and the mucocyst mutant, but is present in initiated and non-initiated cells of the mating mutant (several hypotheses are presented to explain these findings). In addition, ciliary proteins of the mating mutant included at least two unique Con A-binding polypeptides. Our results support the idea that development of mating competence during starvation involves an extensive remodeling of ciliary membranes, and identify a 25 kDa glycoconjugate as having a potential role in control of pair formation during mating.
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PMID:Ciliary polypeptides and glycoconjugates of wild-type and mutant Tetrahymena thermophila: starved versus nonstarved. 139 38

The aim of this study was to determine the feasibility of utilizing a factor Xa-specific cleavage site within a recombinant protein containing the ricin A chain (RTA) sequence. Release of RTA is believed to be an essential step during the intracellular phase of ricin intoxication. Failure to incorporate such cleavage sites in fusions containing RTA results in a loss of toxin action (O'Hare, M., et al. (1990) FEBS Lett. 273,200. Kim, J., and Weaver, R.F. (1988) Gene 68,315). In this report we describe the introduction of a factor Xa-specific site in the linker of proricin, which we use here as a model substrate. Upon purification of the recombinant mutant proricin after expression in Xenopus oocytes, we demonstrate that the protease does have access to the engineered recognition sequence (albeit at low efficiency) and that the presence of the latter does not interfere with disulfide bond formation or the lectin activity of the ricin B chain moiety. Upon cleavage and reduction, the RTA polypeptide displays ribosome-inactivating ability, indicating that the presence of the modified linker at its C-terminus does not interfere with its catalytic activity. The general applicability of using such a cleavage site in recombinant fusions with RTA is discussed.
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PMID:Preparation and characterization of recombinant proricin containing an alternative protease-sensitive linker sequence. 142 Apr 37

Knowledge of the identity, synthesis and secretion of beta-galactoside-binding lectins by leukocytes is of importance because lactosaminoglycans present at the leukocyte cell surface may be physiologically significant lectin receptors that could mediate autocrine or paracrine functions and/or cell adhesion. This paper presents data that show that a previously identified 15.5-16.5 kDa lactose-binding protein synthesized in vitro by human peripheral leukocytes is actually comprised of three different polypeptides. One of these is related to a novel 15 kDa lectin isolated from human spleen and which is synthesized by B lymphoblastoid cells. Spleen contains at least six lactose-binding polypeptides for which the carbohydrate-binding activity is independent of the presence of divalent cations and mercaptoethanol. The splenic 15 kDa polypeptide does not appear to be immunologically related to previously characterized beta-galactoside-binding lectins. It is separable from galaptin, another galactoside-binding lectin (subunit mol. wt 14.5 kDa) by chromatography on DEAE-Sephacel. Western blot analyses and immunoprecipitation/fluorography experiments with metabolically labelled cells showed the presence of the 15 kDa lectin in peripheral leukocytes and in Epstein-Barr virus-immortalized B lymphoblastoid cells. The 15 kDa lectin yielded polypeptide fragments of approximately 6.2 and approximately 8.6 kDa after cyanogen bromide (CNBr) degradation. These fragments were partially sequenced and 12 residues/fragment were identified. A similarity search of the SWISS PROT protein data base did not reveal a relationship of the 15 kDa polypeptide to known lectins, including galaptin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Identification and synthesis of a novel 15 kDa beta-galactoside-binding lectin in human leukocytes. 142 50

Nonhistone proteins were extracted in 0.4 M NaCl from membrane-depleted nuclei of HeLa cells grown in the presence or the absence of [5,6-3H]fucose. Control experiments strongly suggest that most extracted proteins were indeed nuclear components. Several proteins, present in the 0.4 M NaCl nuclear extract, with M(r) ranging from 35,000 to 115,000 were identified on Western blots as fucosylated glycoproteins owing to their binding to the fucose-specific lectin, Ulex europeus agglutinin I. Results of experiments involving mild alkaline treatment and peptide N-glycosidase F digestion showed that the carbohydrate moieties of these fucosylated nuclear glycoproteins were N-linked to the polypeptide backbone. Analysis of the N-glycans revealed the presence of two populations of sialylated oligosaccharides on the basis of their relative molecular masses. The sensitivity of the high-M(r) oligosaccharides to endo-beta-galactosidase and their incorporation of [3H]glucosamine suggest that they could contain repeating N-acetyllactosamine units. [3H]Fucose incorporated into nuclei was confined to the nucleoli, as judged by autoradiography of sections cut through cells grown in the presence of [3H]fucose. Electron microscopy autoradiography showed that the fibrillar centers were never labeled, while silver grains were observed on the dense and the granular components of nucleoli. Taking into account of these data most nuclear fucosylated glycoproteins extracted in 0.4 M NaCl might be nucleolar ribonucleoproteins.
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PMID:Evidence for the presence of complex high-molecular mass N-linked oligosaccharides in intranuclear glycoproteins from HeLa cells. 142 77

Chromatographically purified endopolygalacturonase (PG) from Aspergillus niger was deglycosylated with N-glycosidase F (PNGase F) and characterized by means of sodium dodecyl sulfate (SDS)-electrophoresis, polyacrylamide gel electrophoresis (PAGE) without denaturing agents, isoelectric focusing (IEF) and lectin affino-blotting. The results show that PG, which is apparently homogeneous in SDS-PAGE but heterogeneous in IEF and PAGE, consists of at least two polypeptide chains with different glycosylation patterns. The component with the higher electrophoretic mobility is deglycosylated with PNGase F and reacts with concanavalin A (Con A) and Galanthus nivalis agglutinin (GNA), indicating a "high mannose" or "hybrid"-type of glycoprotein (GP). The other component may contain O-glycosidically linked mannose, N-acetylglucosamine or glucose.
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PMID:Characterization of endopolygalacturonase (EC 3.2.1.15) from Aspergillus niger as glycoprotein by electrophoretic methods and lectin affino-blotting. 145 18

Pumpkin phloem exudate contains two abundant phloem proteins: PP1 is a 96-kD protein that forms polymeric filaments in vivo, and PP2 is a 48-kD dimeric lectin. Polyclonal antibodies raised against pumpkin phloem exudate were used to isolate several cDNAs corresponding to PP1 and PP2. RNA gel blot analysis indicated that PP1 is encoded by an mRNA of approximately 2500 nucleotides, whereas PP2 subunits are encoded by an mRNA of 1000 nucleotides. Sequence analysis of PP2 cDNAs revealed a 654-bp open reading frame encoding a 218-amino acid polypeptide; this polypeptide had the carbohydrate binding characteristics of a PP2 subunit. The PP2 mRNA was localized within the phloem of pumpkin hypocotyl cross-sections based on in situ hybridization of a digoxigenin-labeled antisense probe. PP2 mRNA was found within the companion cells in both the bicollateral vascular bundles and the extrafascicular phloem network.
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PMID:Pumpkin phloem lectin genes are specifically expressed in companion cells. 146 52

beta-Galactoside alpha 2,6-sialyltransferase (SiaT-1), like other glycosyltransferases, is differentially expressed in rat tissues. Two distinct size classes of SiaT-1 mRNAs expressed in rat kidney are comprised of at least three SiaT-1 transcripts. One mRNA, RKE, represents the larger transcript class (4.7 kb) and predicts a polypeptide identical to the hepatic SiaT-1. In transfected Chinese hamster ovary (CHO) cells, RKE polypeptides exhibit hemi-perinuclear staining with a SiaT-1 antibody (Ab-267) that is consistent with Golgi localization. RKE transfectants display cell-surface alpha 2,6-sialic acid linkages as determined by lectin affinity staining. Two other mRNAs, RKA and RKB, are members of a smaller size class (3.6 kb) that comprise predominant SiaT-1 transcripts in rat kidney. Both RKA and RKB encode polypeptides that are missing the amino-terminal 232 residues, but retain 171 amino acids of RKE carboxy-terminal sequence information. A short, leucine-rich peptide present in the divergent amino-terminus of RKA has sequence similarity to the secretory signal domain of several eukaryotic secretory and cell-surface proteins. In transfected CHO cells, both RKA and RKB polypeptides display an immunostaining pattern that is distinct from that of the Golgi-associated SiaT-1 protein (RKE). Furthermore, RKA or RKB transfectants do not display alpha 2,6-sialic acid linkages on cell-surface glycoconjugates. Consistent with the expression of divergent SiaT-1 mRNAs in rat kidney, protein blot analysis of rat tissue homogenates with Ab-267 reveals that in addition to protein that co-migrates with hepatic SiaT-1, rat kidney expresses a unique size class of SiaT-1 proteins.
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PMID:Analysis of kidney mRNAs expressed from the rat beta-galactoside alpha 2,6-sialyltransferase gene. 149 23

We report the cloning and characterization of two lectin genes from Medicago truncatula, designated Mtlec1 and Mtlec2. The two genes show a high degree of homology and apparently belong to a small multigene family. Mtlec1 appears to encode a functional lectin with 277 amino acids, whereas Mtlec2 is probably non-functional, since a frameshift mutation (insertion of two nucleotides) leads to premature translation termination after only 98 amino acids. The deduced amino acid sequence of the polypeptide MtLEC1 suggests that this lectin is a metalloprotein with Glc/Man specificity.
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PMID:Lectin genes from the legume Medicago truncatula. 151 Nov 26


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