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Query: UMLS:C0694563 (eds)
 1,062 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gaucher's disease is a lysosomal storage disease caused by a deficiency in the enzyme glucocerebrosidase. A small, heat-stable glycoprotein first obtained from Gaucher spleen (Ho, M. W., and O'Brien, J. S. (1971) Proc. Natl. Acad. Sci. U. S.A. 68, 2810-2813) has been observed to stimulate the activity of glucocerebrosidase isolated from normal tissue. It has been suggested that this material might be important in the physiological catabolism of glucocerebroside in normal individuals (Ho, M. W. (1974) in Enzyme Therapy in Lysosomal Storage Diseases (Tager, J. M., Hooghwinkel, G. J. M., and Daems, W. Th., eds) pp.239-246, North-Holland Publishing Co., Amsterdam). In order to investigate this suggestion, glucocerebrosidase activating factors were isolated and purified from control and Gaucher spleen and characterized. Although approximately the same mass of activator was isolated from both spleens, the two activators differ from one another in a number of important respects: (a) the activator from the control spleen is only 6 per cent as active (on a protein basis) as the activator from Gaucher spleen; (b) the amino acid compositions of the purified activators are significantly different; and (c) carbohydrate analysis of the purified activators indicates that the activator from Gaucher spleen is a glycoprotein, while that from control spleen is not. Comparative kinetic studies demonstrate that the anionic detergent, sodium taurocholate, and the acidic phospholipid, phosphatidylinositol, both stimulate glucocerebrosidase activity to a larger extent than the activator substance from Gaucher spleen. The activator from Gaucher spleen and human liver glucocerebrosidase both appear to contain significant hydrophobic character. We conclude that the activator is probably not physiologically important in the catabolism of glucocerebroside in normal tissues. The significance of the occurrence of this apparently unique glycoprotein activator in Gaucher spleen remains obscure; however, its presence represents another interesting aspect of Gaucher's disease that warrants further investigation.
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PMID:Purification and properties of a heat-stable glucocerebrosidase activating factor from control and Gaucher spleen. 1 71

Preparations of NADH-ubiquinone reductase from bovine heart mitochondria (Complex I) were shown to contain at least 16 polypeptides by gel electrophoresis in the presence of sodium dodecyl sulphate. 2. High-molecular-weight soluble NADH dehydrogenase prepared from Triton X-100 extracts of submitochondrial particles [Baugh & King (1972) Biochem. Biophys. Res. Commun. 49, 1165-1173] was similar to Complex I in its polypeptide composition. 3. Solubilization of Complex I by phospholipase A treatment and subsequent sucrose-density-gradient centrifugation did not alter the polypeptide composition. 4. Lysophosphatidylcholine treatment of Complex I caused some selective solubilization of a polypeptide of mol.wt. 33000 previosuly postulated to be the transmembrane component of Complex I in the mitochondrial membrane [Ragan (1975) in Energy Transducing Membranes: Structure, Function and Reconstitution (Bennun, Bacila & Najjar, eds.), Junk, The Hague, in the press]. 5. Chaotropic resolution of Complex I caused solubilization of polypeptides of molecular weights 75000, 53000, 29000, 26000 and 15500 and traces of others in the 10000-20000-mol.wt.range. 6. The major components of the iron-protein fraction from chaotropic resolution had molecular weights of 75000, 53000 and 29000, whereas the flavoprotein contained polypeptides of molecular weights 53000 and 26000 in a 1:1 molar ratio. 7. Iodination of Complex I by lactoperoxidase indicated that the water-soluble polypeptides released by chaotropic resolution, in particular those of the flavoprotein fraction, were largely buried in the intact Complex. 8. The polypeptides of molecular weights 75000, 53000, 42000, 39000, 33000, 29000 and 26000 were present in 1:2:1:1:1:1:1 molar proportions. The two subunits of molecular weight 53000 are probably non-identical.
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PMID:The structure and subunit composition of the particulate NADH-ubiquinone reductase of bovine heart mitochondria. 18 Sep 73

Plasma membranes from heart (sarcolemma) were prepared by the method of Kidwai, A.M. (1975) Methods in Enzymology (Fleischer, S. and Packer, L., eds.), Vol XXXIA, pp. 134--144, Academic Press, New York). On many occasions the sarcolemmal fraction identified by the enzyme markers such as (Na+ + K+)-ATPase banded at heavier densities (d greater than 1.25 g/ml) than expected for plasma membrane (d less than 1.15 g/ml). Radio-iodination of the membrane was added as an independent marker and conditions for the reproducible preparation of the sarcolemma were studied. Cultured heart cells were enzymatically iodinated under conditions which did not affect viability and labeled primarily the sarcolemma. The distribution of radioactivity in homogenates of cultured cells on the density gradient corresponded to that of the enzymes' activity. The best sarcolemma preparation was obtained with 0.3 M KCl extraction of heart homogenates in the presence of 0.05 M pyrophosphate, especially if the salt was also present during the fractionation by density gradient centrifugation. Alterations in the density were also observed with erythrocytes and cultured liver cells' plasma membrane. The data suggests a meta-stable state of the plasma membranes due to handling or storage which could cause alterations of some of their physical properties (e.g. density).
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PMID:Plasma membranes from cardiac cells in culture. Enzymatic radio-iodination, evaluation of preparation and properties of the sarcolema. 19 65

Partially purified bovine prothrombin was activated in half-saturated trisodium citrate seeded with thrombin, and the resulting thrombin was chromatographed on Amerblite IRC-50, followed by rechromatography on DEAE-Sephadex A-50. Five fractions, possessing both esterase and clotting activities, were partially isolated, but fraction VI was shown to be a pure three-chain active species with threonine, isoleucine and lysine, in 1:1:1 molar proportions as N-termini. The amino acid composition and C-termini of fraction VI were determinied. The molecular weights of the isolated chains, as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, were 7300, 12000 and 19500 respectively. These data, when taken together with the amino acid sequence of the two-chain thrombin reported by Magnusson et al. (1975) [in Prothrombin and related Coagulation Factors, (Hember, H. C. & Veltkamp, J. J., eds.), pp. 25-46, Leiden University Press, Leiden], indicated that proteolysis occurred at the Arg(78)-Lys(79) peptide bond of the B chain of a precursor molecular species, thus converting this two-chain species into the three-chain active form described here.
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PMID:Isolation and characterization of an active three-chain molecular species of bovine thrombin. 99 41

Digital-imaging fluorescence microscopy with fura-2 allows the determination of intracellular calcium concentration ([Ca2+]i) in single cells. At a cell density of 10(5) cells/petri dish 44% of the chick embryo heart cells had a high [Ca2+]i of 99.4 +/- 7.1 nM and 56% of the cells a low [Ca2+]i of 27.8 +/- 4.4 nM (mean +/- SE). This laboratory previously reported that high-[Ca2+]i and low-[Ca2+]i cells from chick embryo hearts differ in their sensitivity to cardiac glycosides, as shown by measuring the increase in [Ca2+]i to reach a new steady state [Ahlemeyer, B., Weintraut, H., Seibold, G. & Schoner, W. (1991) in The sodium pump: recent developments (Kaplan, J. H. & De Weer, P., eds) pp. 653-656, Rockefeller University Press, New York]. This time we used N-hydroxysuccinimidyl digoxigenin-3-O-methylcarbonyl-epsilon-aminocaproate (HDMA) which binds irreversibly to amino groups of the Na+/K(+)-ATPase, and sheep anti-digoxigenin Fab fragments coupled with fluorescein isothiocyanate to identify different cardiac glycoside-binding sites. Half-maximal labelling of high-[Ca2+]i cells was obtained at 0.36 nM HDMA, and at 12.0 nM with the low-[Ca2+]i cells. Specific labelling of the cells by HDMA was 91% and 80% in high-[Ca2+]i and low-[Ca2+]i cells, respectively, as revealed by competition experiments with a 1000-fold excess of ouabain. HDMA half-maximally elevated the [Ca2+]i of high-[Ca2+]i cells at a concentration of 50 pM and that of low-[Ca2+]i cells at 8.0 nM. Concentrations higher than 0.1 microM produced signs of intoxication. When the labelled cells were subjected to a SDS/PAGE, a 100-kDa band was found to contain HDMA. The electrophoretic mobility of a protein labelled at 10 nM HDMA was slightly higher than that of a protein labelled at 1.0 microM. The data suggest that different isoforms of the alpha-subunit of Na+/K(+)-ATPase may exist in low-[Ca2+]i and high-[Ca2+]i cells of chick embryo heart.
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PMID:Chick heart cells with high intracellular calcium concentration have a higher affinity for cardiac glycosides than those with low intracellular calcium concentration, as revealed by affinity labelling with a digoxigenin derivative. 155 87

Protonated polyamines are among the most efficient cations that induce the left-handed Z-form in certain polynucleotides. It is not known, however, whether these cations bind to specific sites on Z-sequences in solution. We have studied potential polyamine binding sites by measuring the effects of polyamines on the binding of purified immunoglobulins (IgGs) to different regions of the Z-helix and by molecular mechanics modeling. The specific binding of anti-Z-DNA and anti-Z-RNA IgGs to Z-helices was studied as a function of spermidine or spermine concentration. The effect of polyamines on the antibody-nucleic acid interaction was different for IgGs with different specificities for various determinants on the Z-helix. Polyamines inhibit the binding of certain anti-Z IgGs directed against specific sites probably at or near the interface between the major convex surface and the phosphate backbone, most likely by competing with the antibody binding site(s). In contrast, polyamines have no effect on other anti-Z IgGs directed against sites determined by the phosphate backbone. Furthermore, these cations can enhance the binding of anti-Z IgG directed against bulky groups at the C-5 position on the major convex surface of the helix; the enhancement may be related to charge neutralization. Under these conditions, no direct binding of antibodies with polyamines was observed. These data suggest the existence of a specific binding site(s) for polyamines on both Z-DNA and Z-RNA in solution. These binding sites have some similarity to those observed in oligonucleotide crystals by Quigley (in "Molecular Structure and Biological Activity," J.F. Griffin and W.L. Duax, eds., Elsevier, Amsterdam (1982), pp. 317-331). The experimental evidence for specific spermine binding sites on the helical surface was supported by molecular mechanics modeling of the interaction of spermine with the major groove of (dG-dC)5.(dG-dC)5 in both the Z- and B-forms. The crystal coordinates of spermine-containing oligonucleotides in both the B- and Z-forms were used as the starting points for modeling studies. The potential energy of spermine bound to the major convex surface of the Z-form was much less favorable than that of spermine bound to the major groove of the B-form. In the presence of sodium ions, however, the Z-form-spermine complexes were favored over the B-form. Thus, both theoretical and experimental studies indicate that polyamines can specifically recognize Z-helical determinants in solution as well as in crystals.
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PMID:Recognition of Z-RNA and Z-DNA determinants by polyamines in solution: experimental and theoretical studies. 248 66

We have investigated the protein-protein cross-links formed within the 50 S subunit of the Escherichia coli ribosome using 2-iminothiolane as the cross-linking reagent. The members of the cross-links have been identified by immunoblotting from one-dimensional and two-dimensional diagonal sodium dodecyl sulfate-polyacrylamide gels using antisera specific for the individual ribosomal proteins. This method also allowed a quantitation of the yield of cross-linking for each cross-link. A total of 14 cross-links have been identified: L1-L33, L2-L9, L2-L9-L28, L3-L19, L9-L28, L13-L21, L14-L19, L16-L27, L17-L30, L17-L32, L19-L25, L20-L21, L22-L32, and L23-L34. Our results are compared with those of Traut and coworkers (Traut, R. R., Tewari, D. S., Sommer, A., Gavino, G. R., Olson, H. M., and Glitz, D. G. (1986) in Structure, Function and Genetics of Ribosomes (Hardesty, B. and Kramer, G., eds) pp. 286-308, Springer-Verlag, New York). Our cross-linking data allow us to propose the approximate locations of eight proteins of the 50 S ribosomal subunit that so far have not been localized by immunoelectron microscopy and they thus contribute considerably to our knowledge of ribosome structure.
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PMID:Protein-protein cross-linking of the 50 S ribosomal subunit of Escherichia coli using 2-iminothiolane. Identification of cross-links by immunoblotting techniques. 264 89

Leucine aminopeptidase (LAP) was purified from hog lenses by application of the Himmelhoch procedure for isolation of hog kidney LAP [S. R. Himmelhoch (1970) in Methods in Enzymology (Perlmann, G. E., and Lorand, L., eds.), Vol. 19, pp. 508-513, Academic Press, New York.] This involved treating crude hog lens homogenates with hexadecyltrimethylammonium bromide, DEAE-cellulose adsorption and elution, ammonium sulfate fractionation (53-84% of saturation), and gel filtration on a Bio-Gel A-1.5m column. Purifications ranging from 2080- to 4700-fold with activity yields from 28 to 100% were achieved. The hog lens LAP appeared homogeneous by native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE). Bio-Gel chromatography of the native enzyme and SDS-PAGE of dimethylsuberimidate-crosslinked LAP indicated a molecular weight of 326,000. SDS-PAGE of untreated LAP showed a subunit weight of 54,000, consistent with a hexameric enzyme structure. By immunodiffusion, LAP from hog lens and kidney were identical while hog lens and beef lens enzymes demonstrated only partial identity. Electrophoresis of the native enzymes showed a slightly lower mobility for the hog lens LAP than for beef LAP at pH 8.7.
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PMID:Purification, preliminary characterization, and immunological comparison of hog lens leucine aminopeptidase (EC 3.4.11.1) with hog kidney and beef lens aminopeptidases. 392 44

Polyclonal antibodies to calf thymus RNA polymerase II were raised in laying hens. Up to 75 mg of immunoglobulin/egg yolk were extracted by the polyethylene glycol procedure of Roeder (Roeder, R.G. (1976) in RNA Polymerase (Losick, R., and Chamberlin, M., eds) pp. 285-330, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY). The concentration of specific antibody in egg yolks (IgY) was comparable to that of serum as measured by enzyme-linked immunoassay. Purified antibody was shown to be directed against enzyme by removal of enzyme activity in immune complexes precipitated by rabbit anti-chicken IgY. The antibodies recognized several of the subunits of the enzyme as determined by their reactivity with polypeptides transferred to nitrocellulose paper after gradient sodium dodecyl sulfate-gel electrophoresis. Production of antibodies in laying hens may facilitate the study of other highly conserved antigens that are poorly immunogenic in mammalian hosts.
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PMID:Antibodies to calf thymus RNA polymerase II from egg yolks of immunized hens. 633 47

Membrane proteins from vegetative and sporulating cells of Bacillus subtilis were separated by the two-dimensional gel electrophoresis system using isoelectric focusing and sodium dodecyl sulfate/polyacrylamide gel electrophoresis (O'Farrell technique). Membrane proteins were isolated according to published procedures. The gels were stained with Coomassie blue. Three different concentrations of proteins were analyzed to detect even minor constituents. Over two hundred different membrane proteins were identified in vegetative cells by their isoelectric point (pI) and molecular weight (Mr). Analysis of membrane proteins from cells harvested during and at the end of logarithmic growth (A600 approximately equal to 0.8; T0) and every hour thereafter until T4 showed that in the wild-type strain 55 proteins are degraded mostly at the beginning or sporulation. Many others (76 proteins) are newly synthesized during sporulation. About 16 proteins are synthesized at times during sporulation but again degraded within 1 h or less. Others (uncertain proteins, 65) are degraded and resynthesized again. This observation is in agreement with experiments previously published by Andreoli et al. [Andreoli, A. J., Kao, M., Chui, R., Cabrera, J., and Wong, S. K. S (1981) in Sporulation and Germination (Levinson, H. S., Sonenshein, A. L., and Tipper, D. J., eds) pp. 168-173, American Society for Microbiology, Washington] using Bacillus cereus. Experiments with the early blocked asporogenous mutant JH 649 (spoOF) showed that few proteins (40%) are degraded and even fewer (30%) are newly synthesized between A600 approximately equal to 0.8 and T4. Protease inhibitors (phenylmethylsulfonyl fluoride, EDTA, o-phenanthroline) have no effect on the protein patterns. The experiments presented here show that proteins involved in differentiation in B. subtilis can be identified by the two-dimensional gel electrophoresis system and with the aid of asporogenous mutants. In order to assure that no cytoplasmic proteins are contaminating the membrane preparations, several cytoplasmic enzyme activities have been measured. Their concentration was found to be always below 0.005% of total protein, which is below the level of detection by Coomassie blue staining.
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PMID:Changes in membrane-associated proteins during sporulation in Bacillus subtilis. 642 83


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