International Journal of Biochemistry最新文献

{"title":"Characterization of human arylsulfatase a glycans","authors":"Piotr Laidler ,&nbsp;Anna Litynska ,&nbsp;Maria Galka-Wakczak ,&nbsp;Boguslaw Wojczyk","doi":"10.1016/0020-711X(94)90183-X","DOIUrl":"10.1016/0020-711X(94)90183-X","url":null,"abstract":"<div><p>Despite numerous studies on arylsulfatase A, the structure of the glycans present in each of its two subunits has not been determined. This is important because the carbohydrate component of human arylsulfatase A synthesized in tumor tissues and transformed cells has been shown to undergo apparent changes. This study elucidates some of their major features.</p><p>Glycan chain analysis of native and deglycosylated arylsulfatase A as well as its subunits was performed with the use of a Glycan Differentiation Kit and lectin affinity chromatography. Each of the two subunits of arylsulfatase A from placenta, separated electrophoretically on polyacrylamide gel in reducing conditions, reacted with digoxigenin-labelled <em>Galantus nivalis</em> agglutinin and <em>Aleuria awantia</em> agglutinin, while those from liver enzyme reacted with the former only. The subunits of both enzymes did not react with <em>Sambucus nigra</em>, <em>Maakia amuriensis</em>, <em>Datura stramonium</em> or Peanut agglutinin. Deglycosylation of arylsulfatase A with peptide <em>N</em>-glycosidase F and endo-β-<em>N</em>-acetylglucosaminidase F resulted in complete cleavage of its carbohydrate component from each subunit. Their molecular weights decreased by 3 kDa. Neuraminidase treatment of the enzyme from liver and placenta followed by isoelectrofocusing separation showed the presence of sialylated forms which constituted a small percentage of total enzyme activity. Placental arylsulfatase A became bound to <em>Lens culinaris</em> agglutinin agarose, while no interaction with <em>Ricinus communis</em> or <em>Griffonia simplicifolia</em> agglutinin agarose was observed.</p><p>The study shows that both subunits of arylsulfatase A from human placenta possess two high mannose/hybrid type glycans as major structures, with at least one 6-<em>O</em>-<span>l</span>-fucose bound to the innermost <em>N</em>-acetylglucosamine on each. The enzyme from liver does not possess fucose. Complex type glycans containing sialic acid constitute a small percentage of the total carbohydrate component.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 12","pages":"Pages 1395-1401"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90183-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18888619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Induction of cytochrome P450 by toluene","authors":"Tamie Nakajima,&nbsp;Rui-Sheng Wang","doi":"10.1016/0020-711X(94)90175-9","DOIUrl":"10.1016/0020-711X(94)90175-9","url":null,"abstract":"<div><p>At least six cytochrome <em>P</em>450 (<em>P</em>450) isoenzymes, including CYP1A1/2, CYP2A1, CYP2B1/2, CYP2C6, CYP2C11 and CYP2E1, are involved in the metabolism of toluene in rat liver. Toluene exposure induces CYP1A1/2, CYP2B1/2, CYP2E1 and CYP3A1, but decreases CYP2C11/6 and CYP2A1 in adult males. Both sex and age influence the induction of <em>P</em>450s by toluene: in general, the inductive effect is more prominent in younger than in older animals; in males than in females. Neonatal exposure to toluene causes significant changes in liver microsomal <em>P</em>450 dependent monooxygenase activities during the early stage of life, whereas the enects on the rats of more than 3 weeks of age are small. Although structurally related chemicals of toluene also influence similar hepatic <em>P</em>450 isoenzymes, the degree of CYP2B1/2 induction increases, whilst that of CYP2E1 decreases with increasing molecular weight and aliphatic moieties. Unlike liver, exposure to toluene does not influence the distribution of pulmonary or renal microsomal <em>P</em>450-related enzyme activity in rats. In humans, occupational exposure to toluene is so low that it could not lead to the induction of <em>P</em>450. However, the induction may be seen in toluene sniffers who are exposed to high concentrations.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 12","pages":"Pages 1333-1340"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90175-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18888074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The 5'-sequence of the murine Hox-b3 (Hox-2.7) gene and its intron contain multiple transcription-regulatory elements","authors":"William M. Brown ,&nbsp;Gareth R. Taylor","doi":"10.1016/0020-711X(94)90184-8","DOIUrl":"10.1016/0020-711X(94)90184-8","url":null,"abstract":"<div><p>We sought to clone and characterize the murine <em>Hox-b</em>3 gene. In <em>Xenopus</em> embryos, the homologous gene has been shown to be responsive to retinoic acid, an agent which has profound effects on tissue growth and development. By plaque hybridization, using a partial, murine <em>Hox-b</em>3 cDNA as a probe, we screened a genomic library and isolated a series of overlapping clones. Restriction fragments from positive clones were sequenced by the dideoxy method on an automated DNA sequencer.</p><p>We report the genomic sequence of the murine <em>Hox-b</em>3 gene. The sequence has been submitted to the GenBank database (accession number U02278). Our sequence extends from the P1 promoter through the coding sequence of the gene to the 3'-untranslated region. In common with other homeobox genes, there is an intron between the conserved hexapeptide and the homeobox. It is 866 bp long and has 3'- and 5'-splice sites very similar to the consensus, a long polypyrimidine tract and a potential branch point near the 3'-splice site. We have analyzed the sequence 5' to the initiation codon and the intron for putative control elements, and have identified a series of putative transcription factor binding sites in the P1 promoter and intron, including two for the retinoid X receptor-β. Their possible significance is discussed.</p><p>The sequences we have identified may be responsible for the observed pattern of expression of the gene. This sequence and the clones from which it is derived will enable a molecular dissection of the P1 promoter region.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 12","pages":"Pages 1403-1409"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90184-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18888620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Partial purification and further characterization of the novel endoglucosaminidase from human serum that hydrolyses 4-methylumbelliferyl-N-acetyl-β-d-chitotetraoside (MU-TACT hydrolase)","authors":"B. Overdijk ,&nbsp;G.J. Van Steijn ,&nbsp;W.R. Den Tandt","doi":"10.1016/0020-711X(94)90179-1","DOIUrl":"10.1016/0020-711X(94)90179-1","url":null,"abstract":"<div><p>A novel endoglucosaminidase, originally described by Den Tandt <em>et al.</em> [<em>Int. J. Biochem.</em><strong>20</strong> (1988), 713–719] and bearing the provisional name MU-TACT hydrolase, was purified from human serum 56,000-fold by means of ammonium sulphate precipitation, anion-exchange chromatography, Con A-Sepharose chromatography and gel filtration on Sepharose CL-6B followed by Superose 12HR. Based on the latter technique the native apparent molecular weight of the enzyme appeared to be equal to that of myoglobin, being approx. 17 kD. The enzyme eluted clearly at a different volume than lysozyme. MU-TACT is a commercially available substrate for lysozyme. For unknown reasons two major peptides co-purify that give bands on SDS-PAGE of 55–60 and 31 kD, respectively.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 12","pages":"Pages 1369-1375"},"PeriodicalIF":0.0,"publicationDate":"1994-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90179-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18888615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alanine aminopeptidase of guinea-pig brain: A broad specificity cytoplasmic enzyme capable of hydrolysing short and intermediate length peptides","authors":"Maria Smyth ,&nbsp;Gerard O'Cuinn","doi":"10.1016/0020-711X(94)90098-1","DOIUrl":"10.1016/0020-711X(94)90098-1","url":null,"abstract":"<div><p>Alanine aminopeptidase is reported to be a broad specificity aminopeptidase acting on peptides of different lengths. In this study we wish to define the properties of the activity from guinea-pig brain and compare these properties with previous findings. Alanine aminopeptidase was purified from cytoplasm of guinea-pig brain by a four-step procedure involving chromatography on DE-52, hydroxylapatite, Sephacryl S-200 and DEAE-Sephacryl. Relative molecular mass was determined by chromatography on Sephacryl S-200 column and subunit size determined by SDS-PAGE under denaturing conditions. Cations which reactivate the enzyme were determined with EDTA treated enzyme. Substrate specificity was determined by TLC and kinetic parameters were derived from Lineweaver-Burk plots. A 216-fold purification was achieved by the above procedures. The purified enzyme was found to consist of one polypeptide chain with a relative molecular mass of 104,000. Its activity was inhibited by chelating agents, sulphydryl reactive agents, puromycin, bestatin and amastatin but stimulated over 6-fold by dithiothreitol. Some dipeptides and all tripeptides and longer peptides containing up to 16 amino acids tested were hydrolysed provided neither Gip or Pro occurred at the N-terminus or that Pro did not occur in the penultimate position from the N-terminus. The enzyme preferred bulky non-polar residues at the N-terminal and penultimate positions and was found to hydrolyse three dipeptidyl methyl coumarin amides used in detecting dipeptidyl aminopeptidases. Alanine aminopeptidase is thus a broad specificity aminopeptidase acting on short and intermediate length peptides whose affinity for substrates increases with increasing peptide length. Its properties are well suited to a role in peptide turnover in brain cytoplasm.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 10","pages":"Pages 1287-1297"},"PeriodicalIF":0.0,"publicationDate":"1994-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90098-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18849949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cytochrome P450 changes in rats with streptozocin-induced diabetes","authors":"Nobuo Shimojo","doi":"10.1016/0020-711X(94)90095-7","DOIUrl":"10.1016/0020-711X(94)90095-7","url":null,"abstract":"<div><p>It is known that the metabolism of some drugs is altered in diabetic patients and in rats with experimental diabetes induced by chemical agents, such as streptozocin. The induction and/or suppression of hepatic cytochrome <em>P</em>450 isozymes seen in diabetes seem to contribute to this alteration. Both metabolic and hormonal disturbances following insulin deficiency in diabetic rats are responsible for these changes. Marked changes in hepatic <em>P</em>450 isozymes in diabetic rats include increases in the isozymes induced by ketones and lipids, including fatty acids, and decreases in the isozymes regulated by growth hormone and testosterone. Suppressed secretion of thyroid hormones also participates in the mechanism causing these changes. Analysis of cytochrome <em>P</em>450 isozymes in diabetic rats is helpful in elucidating the impaired metabolism of some endogenous substrates catalyzed by the cytochrome <em>P</em>450, such as steroid hormones and fatty acids, in diabetes. The results of these analyses also provide insight into the prescription of drugs for diabetic patients.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 10","pages":"Pages 1261-1268"},"PeriodicalIF":0.0,"publicationDate":"1994-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90095-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18880696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modulation of nerve and glial function by adenosine—role in the development of ischemic damage","authors":"Peter Schubert ,&nbsp;Karl A. Rudolphi ,&nbsp;Bertil B. Fredholm ,&nbsp;Yoichi Nakamura","doi":"10.1016/0020-711X(94)90092-2","DOIUrl":"10.1016/0020-711X(94)90092-2","url":null,"abstract":"<div><p>Adenosine is released during brain ischemia and provides neuroprotection by actions on nerve and glial cells. Activation of the adenosine A₁ receptor enhances the K⁺ and Cl conductance in neurons, leading to membrane hyperpolarization and postsynaptic reduction of neuronal Ca²⁺ influx through voltage- and NMDA receptor-dependent channels. In addition adenosine A₁ receptor activation decreases excitatory amino acid release, possibly via inhibition of N- and P-type Ca²⁺ channels. The A₁ and A₂ receptors, coupled to G₁/G_o and G_s proteins respectively, often co-exist and interact with the phospholipase C-dependent activation of the protein kinase C and the adenylyl cyclase. Activation of the A₁ receptor may mimic metabotropic receptor stimulation in activating intracellular Ca²⁺ mobilization and PKC. A₂ receptor mediated cAMP formation is depressed by high intracellular Ca²⁺ but enhanced by PKC activation. By modulating these metabolic signaling events, adenosine may influence acute cell functions, gene transcription and sustained changes of nerve and glial cells relevant for the development of ischemic damage. The neuroprotective adenosine effect seems to be amplified by treatment with propentofylline, which enhances adenosine release, influences the balance between A₁ and A₂. receptor mediated actions, depresses the free radical formation in activated microglia and influences astrocyte reactions.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 10","pages":"Pages 1227-1236"},"PeriodicalIF":0.0,"publicationDate":"1994-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90092-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18539067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ostrich pancreatic α-amylase: Kinetic properties, amino terminal sequence and subsite structure","authors":"Vaughan Oosthuizen ,&nbsp;Ryno J. Naudé ,&nbsp;Willem Oelofsen ,&nbsp;Koji Muramoto ,&nbsp;Hisao Kamiya","doi":"10.1016/0020-711X(94)90101-5","DOIUrl":"10.1016/0020-711X(94)90101-5","url":null,"abstract":"<div><p>Ostrich pancreatic α-amylase (OPA) was purified to homogeneity in the presence of protease inhibitors by a single-step affinity chromatography technique. The first 53 amino acids of the N-terminus were identified by gas-phase sequencing. From kinetic parameters (<em>k</em>_cat/<em>K</em>_m) a subsite profile was established leading to a five subsite model for OPA. The pK_<em>a</em> values of catalytic residues were determined as 5.75 and 8.36. Inhibition of OPA by monosaccharides, β-cyclodextrin and a wheat α-amylase inhibitor was studied.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 10","pages":"Pages 1313-1321"},"PeriodicalIF":0.0,"publicationDate":"1994-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90101-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84563086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cell surface glycoconjugates as modulators of embryo attachment to uterine epithelial cells","authors":"Daniel D. Carson,&nbsp;Larry H. Rohde,&nbsp;Gulnar Surveyor","doi":"10.1016/0020-711X(94)90096-5","DOIUrl":"10.1016/0020-711X(94)90096-5","url":null,"abstract":"<div><p>Attachment of mammalian embryos to the uterine wall involves the coordinated development of both the embryo and the uterine epithelium to an attachment-competent state. This coordination is achieved directly or indirectly through the actions of ovarian steroids. Acquisition of attachment competence is proposed to reflect two processes. The first is the loss of non-adhesive glycoproteins at the cell surface of embryos, e.g. zona pellucida subunits, as well as uterine epithelial cells, e.g. mucin glycoproteins. The second process is the functional expression of complementary adhesion-promoting molecules at these cell surfaces. A series of studies indicates that heparan sulfate proteoglycans and their corresponding binding sites can play an important role in the initial stage of embryo attachment to the uterine surface.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 10","pages":"Pages 1269-1277"},"PeriodicalIF":0.0,"publicationDate":"1994-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90096-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18849953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Purification of a cytosolic enzyme from human liver with phospholipid hydroperoxide glutathione peroxidase activity","authors":"Stephen J. Chambers,&nbsp;Nigel Lambert,&nbsp;Gary Williamson","doi":"10.1016/0020-711X(94)90097-3","DOIUrl":"10.1016/0020-711X(94)90097-3","url":null,"abstract":"<div><p>Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenoprotein which inhibits peroxidation ofmicrosomes. The human enzyme, which may play an important role in protecting the cell from oxidative damage, has not been purified or characterized. PHGPx was isolated from human liver using ammonium sulphate fractionation, affinity chromatography on bromosulphophthalein-glutathione-agarose, gel filtration on Sephadex G-50, anion exchange chromatography on Mono Q resin and high resolution gel filtration on Superdex 75. The protein was purified about 112,000-fold, and 12 μg, was obtained from 140 g of human liver with a 9% yield. PHGPx was active on hydrogen peroxide, cumene hydroperoxide, linoleic acid hydroperoxide and phosphatidylcholine hydroperoxide. The molecular weight, as estimated from non-denaturing gel filtration, was 16,100. The turnover number (37°C, pH 7.6) on (β-(13-hydroperoxy-<em>cis</em>-9, <em>trans</em>-11-octadecadienoyl)-γ-palmitoyl)-<span>l</span>-α-phosphatidylcholine was 91 mol mo⁻¹ s⁻¹. As reported for pig PHGPx, activity of the enzyme from human liver on cumene hydroperoxide and on linoleic acid hydroperoxide was inhibited by deoxycholate. In the presence of glutathione, the enzyme was a potent inhibitor of ascorbate/Fe induced lipid peroxidation in microsomes derived from human B lymphoblastic AHH-1 TK ± CHol cells but not from human liver microsomes. Human cell line microsomes contained no detectable PHGPx activity. However, microsomes prepared from human liver contained 0.009 U/mg of endogenous PHGPx activity, which is 4–5 times the activity required for maximum inhibition of lipid peroxidation when pure PHGPx was added back to human lymphoblastic cell microsomes. PHGPx from human liver exhibits similar properties to previously described enzymes with PHGPx activity isolated from pig and rat tissues, but does not inhibit peroxidation of human liver microsomes owing to a high level of PHGPx activity already present in these microsomes.</p></div>","PeriodicalId":13733,"journal":{"name":"International Journal of Biochemistry","volume":"26 10","pages":"Pages 1279-1286"},"PeriodicalIF":0.0,"publicationDate":"1994-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0020-711X(94)90097-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18851224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}