Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chemical relationship of the seven forms of human liver alpha-L fucosidase has been studied by isoelectric focusing of neuraminidase- and sialytransferase-treated preparations of alpha-L-fucosidase. Neuraminidase treatment leads to a decrease in the activity of the more acidic forms (IV-VII) and a concimitant increase in the activity of the more neutral forms (I-II). Incubation of the neuraminidase-treated fucosidase (forms I-III) with radiolabelled cytidine monophosphate-N-3H-acetylneuraminic acid and an enriched preparation of sialytransferase devoid of fucosidase activity led to regeneration of the more acidic fucosidase isoenzymes (IV-VII) with the same isoelectric points and in nearly the same proportion as before neuraminidase treatment. These experiments suggest that the isoenzymes of human liver alpha-L-fucosidase are related, at least in part, by sialic acid residues. The seven isoenzymes of purified human liver alpha-L-fucosidase have been separated by preparative isoelectric focusing and characterized kinetically and immunochemically. Differences in Michaelis constants (Km's) and pH optimum curves were found for some of the isoenzymes. All seven isoenzymes were immunoprecipitated using the IgG fraction of anti-alpha-L-fucosidase antiserum suggesting that the presence of sialic acid residues does not affect the antigenicity of the forms of alpha-L-fucosidase.
Mol Cell Biochem 1978 May 31
PMID:Isoenzymes of human liver alpha-L-fucosidase: chemical relationship, kinetic studies, and immunochemical characterization. 2 63

The steroid complexes of (plasma) corticosteroid-binding globulin can be distinguished from intracellular steroid-receptor complexes by agar electrophoresis at low temperature in neuraminidase-treated tissue extracts. With this method, the presence of progesterone receptor has been demonstrated in heavily plasma-protein-contaminated human uterus "cytosol", but not in human mammary carcinoma extracts. SHBG and "basic" receptors for estradiol and dihydrotestosterone in human uterus cytosol could also be assayed simultaneously.
Mol Cell Endocrinol
PMID:Differentiation between steroid hormone receptors CBG and SHBG in human target organ extracts by a single-step assay. 17 88

1. In a patient with I-cell disease the activities of several acid hydrolases were elevated inplasma and reduced in cultured fibroblasts when compared with normal values. Normal activities for the enzymes were found in leucocytes. These findings agree with reports on other cases. 2. N-Acetyl-beta-D-glucosaminidase was resolved into its component forms by chromatography on microcolumns of DEAE-cellulose coupled with continuous automated assay of activity in the column effluent. Cultured skin fibroblasts from three patients showed a profound deficiency of glucosaminidase component A and a relative increase in the activity of a form eluted earlier than A. 3. In the one patient studied, the elution profile of plasma glucosaminidase was similar to that of normal plasma, but treatment with neuraminidase revealed a minor component which did not appear in control specimens. 4. Chromatographic resolution of glucosaminidase secreted by normal fibroblasts into the culture medium shoed that component A comprised two forms, a serum-type and a tissue-type, whereas only a serum-type was found in I-cell medium. 5. Different forma of alpha-L-fucosidase were shown to occur in normal plasma and fibroblasts. This is the second lysosomal hydrolase for which differences between intracellular and extracellular forms have been described and might reflect a general phenomenon. 6. The major acidic component of fucosidase from normal fibroblasts was not detected in I-cell fibroblasts. Elution profiles of fucosidase activity in normal and I-cell plasma were indistinguishable, both before and after treatment with neuraminidase. 7. On the basis of the above findings, we suggest that for several acid hydrolases there is a common biosynthetic reaction, which produces forms of these enzymes destined for incorporation into primary lysosomes rather than secretion by the cell. In cultured fibroblasts from patients with I-cell disease, the enzyme catalysing the reaction leading to the production of intracellular forms is deficient or defective, whereas the synthesis of precursor and secreted forms is unaffected.
Clin Sci Mol Med 1975 Dec
PMID:I-cell disease (mucolipidosis II): resolution of N-acetyl-beta-D-glucosaminidase and alpha-L-fucosidase components by DEAE-cellulose chromatography. 120 84

The sialidase from Salmonella typhimurium LT2 was characterized by using photoaffinity-labelling techniques. The well-known sialidase inhibitor 5-acetamido-2,6-anhydro-3,5-dideoxy-D-glycero-D-galacto-non- 2-enonic acid (Neu5Ac2en) was modified to contain an amino group at C-9, which permitted the incorporation of 4-azidosalicylic acid in amide linkage at this position. Labelling of the purified protein with the radioactive (125I) photoprobe was determined to be highly specific for a region within the active-site cavity. This conclusion was based on the observation that the competitive inhibitor Neu5Ac2en in the photolysis mixture prevented labelling of the protein. In contrast, compounds with structural and chemical features similar to the probe and Neu5Ac2en, but which were not competitive enzyme inhibitors, did not affect the photolabelling of the protein. The peptide interacting with the probe was identified by CNBr treatment of the labelled protein, followed by N-terminal sequence analysis. Inspection of the primary structure of the protein, predicted from the cloned structural gene for the sialidase [Hoyer, Hamilton, Steenbergen & Vimr (1992) Mol. Microbiol. 6, 873-884] revealed that the label was incorporated into a 9.6 kDa fragment situated within the terminal third of the molecule near the C-terminal end. Secondary-structural predictions using the Garnier-Robson algorithm [Garnier, Osguthorpe & Robson (1978) J. Mol. Biol. 120, 97-120] of the labelled peptide revealed a structural similarity to the active site of influenza-A- and Sendai-HN-virus sialidases with a repetitive series of alternating beta-sheets connected with loops.
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PMID:Photolabelling of Salmonella typhimurium LT2 sialidase. Identification of a peptide with a predicted structural similarity to the active sites of influenza-virus sialidases. 129 92

We have investigated the binding of 125I-staphylococcal enterotoxin-B (SEB) in cultured human proximal tubular cells. We found that the binding of 125I-SEB to PT cells was time and concentration dependent and competitively inhibited by antibody against SEB. Preincubation of cells with trypsin and neuraminidase or with fetuin did not significantly impair the binding of 125I-SEB to such cells. In contrast, treatment with endoglycoceramidase completely inhibited the binding of 125I-SEB to cells. Neutral glycosphingolipids exerted a concentration-dependent inhibition of 125I-SEB binding to such cells, maximum inhibition (96% compared to control) occurred upon incubation of PT cells with neutral glycosphingolipids. Taken together, our studies indicate that SEB specifically binds to a neutral glycosphingolipid in PT cells. In contrast, staphylococcal enterotoxin-A and toxic shock toxin (TST-1) are bound to a protein in such cells.
Mol Cell Biochem 1992 Jul 06
PMID:Glycosphingolipids: the putative receptor for Staphylococcus aureus enterotoxin-B in human kidney proximal tubular cells. 132 93

We have characterized the ANF-R2 receptor-mediated inhibition of adenylate cyclase with respect to its modulation by several regulators. ANF (99-126) inhibits adenylate cyclase activity only in the presence of guanine nucleotides. The maximal inhibition (approximately 45%) was observed in the presence of 10-30 microM GTP gamma S, and at higher concentrations, the inhibitory effect of ANF was completely abolished. ANF-mediated inhibition was not dependent on the presence of monovalent cations, however Na+ enhanced the degree of inhibition by about 60%, whereas K+ and Li+ suppressed the extent of inhibition by about 50%. On the other hand, divalent cation, such as Mn2+ decreased the degree of inhibition in a concentration dependent manner, with an apparent Ki of about 0.7 mM, and at 2 mM; the inhibition was completely abolished. In addition, proteolytic digestion of the membranes with trypsin (40 ng/ml) resulted in the attenuation of ANF-mediated inhibition of adenylate cyclase. Other membrane disrupting agents such as neuraminidase and phospholipase A2 treatments also inhibited completely, the ANF-mediated inhibition of enzyme activity. N-Ethylmaleimide (NEM), phorbol ester and Ca(2+)-phospholipid dependent protein kinase (C-kinase) which have been shown to interact with inhibitory guanine nucleotide regulating protein (Gi) also resulted in the attenuation of ANF-mediated inhibition of adenylate cyclase activity. These results indicate that in addition to the Gi, the phospholipids and glycoproteins may also play an important role in the expression of ANF-R2 receptor-mediated inhibition of adenylate cyclase.
Mol Cell Biochem 1992 Jul 06
PMID:Characterization of ANF-R2 receptor-mediated inhibition of adenylate cyclase. 132 94

The effect of lengthening the distance in an adhesion molecule between the receptor binding site and the membrane anchor was studied by inserting four Ig-like domains into the two Ig domain lymphocyte function-associated antigen 3 (LFA-3) molecule. The extended molecule expressed in Chinese hamster ovary (CHO) cells bound to CD2 on T lymphocytes 4- to 20-fold more efficiently than the wild-type molecule at 4 degrees C. Treatment of the CHO clones with neuraminidase to remove sialic acid, or with deoxymannojirimycin to reduce the bulk of N-linked glycosylation, showed that adhesion to both the wild-type and the chimeric LFA-3 molecules was under the influence of cell-cell repulsive forces to a similar extent and that these treatments had less effect than lengthening LFA-3. At higher temperatures, such as 22 and 37 degrees C, the efficiency of binding to the wild-type LFA-3 increased to levels comparable with binding to extended LFA-3. Our results suggest that more distal locations of the adhesive binding site from the cell membrane anchor increase the efficiency of cell-cell adhesion by enhancing the frequency of receptor encounter with ligand and that more proximal locations of the adhesive binding site can provide efficient cell-cell adhesion at physiological temperatures.
Mol Biol Cell 1992 Feb
PMID:Effect of lengthening lymphocyte function-associated antigen 3 on adhesion to CD2. 134 6

We have previously shown that a polyclonal (rabbit anti-TCNA) and a mouse monoclonal antibody (TCN-2) against the neuraminidase of Trypanosoma cruzi (TCNA) inhibit enzyme activity, immunoprecipitate active enzyme, enhance in vitro infection, and identify a subpopulation of extracellular trypomastigotes. We now report on the identification of a synthetic peptide that contains the epitope recognized by these antibodies. The synthetic peptide (TR) is a dodecamer (D-S-S-A-H-G-T-P-S-T-P-A) deduced from the DNA sequence of the long tandem repeat (LTR) domain present in the TCNA carboxyterminus. By ELISA, rabbit anti-TCNA bound to TR coupled to ovalbumin, and the binding was inhibited by soluble TR but not by BR (Y-S-V-D-D-G-E-T-W-E), a peptide derived from the N-terminal domain of the enzyme. TCN-2 recognized TR, and this reaction as well as TCN-2 binding to endogenous TCNA could be inhibited by soluble TR but not by BR. These results indicate that the rabbit anti-TCNA and TCN-2 react with the LTR region of TCNA. Antibodies to TR reacted by immunoblot with the TCNA of the Silvio X-10/4, MV-13 and Y-H6 strains, identifying the same molecular polymorphism previously observed with the rabbit anti-TCNA and TCN-2. Furthermore, anti-TR antibodies immunoprecipitated active enzyme and immunofluorescence analysis revealed that anti-TR and TCN-2 antibodies detected equally well the differential expression of their epitopes in intra- and extracellular trypomastigotes. Moreover, expression of TR and TCN-2 epitopes on the different stages of T. cruzi paralleled the stage-specificity of TCNA activity. TCN-2 prevented desialylation by TCNA of intact cells but not of soluble glycoconjugates, indicating that TCN-2 epitope is probably not associated with the enzyme catalytic site, in agreement with the predicted sequence of the TCNA gene. Finally, analysis of the humoral response of a Chagasic patient to different areas of the TCNA molecule indicated that the antibody response is predominantly against TR suggesting that the tandem repeat is the immunodominant domain of TCNA.
Mol Biochem Parasitol 1992 May
PMID:Mapping of a B-cell epitope present in the neuraminidase of Trypanosoma cruzi. 137 12

The crystal structure of the complex between neuraminidase from influenza virus (subtype N9 and isolated from an avian source) and the antigen-binding fragment (Fab) of monoclonal antibody NC41 has been refined by both least-squares and simulated annealing methods to an R-factor of 0.191 using 31,846 diffraction data in the resolution range 8.0 to 2.5 A. The resulting model has a root-mean-square deviation from ideal bond-length of 0.016 A. One fourth of the tetrameric complex comprises the crystallographic model, which has 6577 non-hydrogen atoms and consists of 389 protein residues and eight carbohydrate residues in the neuraminidase, 214 residues in the Fab light chain, and 221 residues in the heavy chain. One putative Ca ion buried in the neuraminidase, and 73 water molecules, are also included. A remarkable shape complementarity exists between the interacting surfaces of the antigen and the antibody, although the packing density of atoms at the interface is somewhat looser than in the interior of a protein. Similarly, there is a high degree of chemical complementarity between the antigen and antibody, mediated by one buried salt-link, two solvated salt-links and 12 hydrogen bonds. The antibody-binding site on neuraminidase is discontinuous and comprises five chain segments and 19 residues in contact, whilst 33 neuraminidase residues in eight segments have 899 A2 of surface area buried by the interaction (to a 1.7 A probe), including two hexose units. Seventeen residues in NC41 Fab lying in five of the six complementarity determining regions (CDRs) make contact with the neuraminidase and 36 antibody residues in seven segments have 916 A2 of buried surface area. The interface is more extensive than those of the three lysozyme-Fab complexes whose crystal structures have been determined, as judged by buried surface area and numbers of contact residues. There are only small differences (less than 1.5 A) between the complexed and uncomplexed neuraminidase structures and, at this resolution and accuracy, those differences are not unequivocal. The main-chain conformations of five of the CDRs follow the predicted canonical structures. The interface between the variable domains of the light and heavy chains is not as extensive as in other Fabs, due to less CDR-CDR interaction in NC41. The first CDR on the NC41 Fab light chain is positioned so that it could sterically hinder the approach of small as well as large substrates to the neuraminidase active-site pocket, suggesting a possible mechanism for the observed inhibition of enzyme activity by the antibody.(ABSTRACT TRUNCATED AT 400 WORDS)
J Mol Biol 1992 Sep 05
PMID:Refined crystal structure of the influenza virus N9 neuraminidase-NC41 Fab complex. 138 57

A genomic clone, pTt21, containing DNA apparently transcribed specifically in Trypanosoma cruzi trypomastigotes, was obtained by differentially screening a genomic library with trypomastigote and epimastigote cDNA. This 3444-bp clone contained open reading frames at each end, separated by a 1.8-kb non-coding region. The translated polypeptide from the 3' open reading frame (ORF2) of 1037 bp had 25-30% identity with 5 recently published T. cruzi gp85/sialidase sequences, and 20-25% identity with bacterial sialidases. Rabbit antiserum raised against an Escherichia coli fusion protein derived from the 5' open reading frame (ORF1) identified a surface antigen of 160 kDa, specifically expressed in trypomastigotes. A probe containing the first 211 bp from ORF1 was used to obtain a complete copy (c1821) of a gene that was closely related to ORF1, and encoded another member of the gp85/sialidase family. c1821 encodes a protein of 897 amino acids, but assignment of the N-terminus of the polypeptide was not possible. The 5'-most start codon is an unfavourable context to act as a translation initiator, it does not align with the initiator methionines of other gp85/sialidase sequences, nor is it followed by a signal peptide sequence characteristically found in other gp85/sialidase sequences. Although homology with the 5' ends of other gp85/sialidase sequences decays towards the 5' end of c1821, alignment of c1821 with 4 other gp85/sialidases indicated that the coding sequence should extend upstream at least 160 amino acids. In this region of c1821 there are multiple stop codons in each frame. The presence of the stop codons, the alignment data and our inability to amplify reverse transcribed mRNA using four internal primers, suggest that c1821 may not be present as a mature mRNA and is a pseudogene. Comparison of the apparently non-repetitive 3' coding domain of c1821 with the corresponding repetitive domains of two other members of the gp85/sialidase family revealed a high degree of similarity in nucleotide but not in amino acid sequence, and c1821 may thus represent an evolutionary intermediate between sub-families of the gp85/sialidase superfamily.
Mol Biochem Parasitol 1992 Nov
PMID:Sequence homology and absence of mRNA defines a possible pseudogene member of the Trypanosoma cruzi gp85/sialidase multigene family. 147 90


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