Biochemistry international (Biochem Int)

Publications in this journal

• Article: The influence of glycolate on lipid turnover in mouse tissues

  D Crane, RS Holmes CJ Masters
  Biochemistry international 02/2013; 1:133-138.
• Article: Immunodetection of tubulin carboxypeptidase activity on nitrocellulose membrane after gel electrophoresis and blotting.

  A M Smania, C E Argaraña, J C Weizetfel, H S Barra
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  ABSTRACT: It was found that the detyrosination of tyrosinated tubulin by tubulin carboxypeptidase can occur when both the enzyme and the substrate are adsorbed on nitrocellulose. This, and the use of a specific antibody that recognizes detyrosinated tubulin allowed us to localize tubulin carboxypeptidase on a nitrocellulose membrane after agarose gel electrophoresis and blotting. The method was also extended to detect pancreatic carboxypeptidase A.
  Biochemistry international 01/1993; 28(5):921-8.
• Article: Characterization of trehalase in Rhodotorula rubra.

  J J Mansure, J T Silva, A D Panek
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  ABSTRACT: Trehalase activity in Rhodotorula rubra was found to be bound to the particulate fraction of a cell-free extract in contrast with the soluble trehalase activity of Saccharomyces cerevisiae. The enzyme was strongly repressed by glucose and derepressed during growth on maltose, trehalose and glycerol. This increase in activity was due to a "de novo" synthesis as seen by inhibition with cycloheximide, a mechanism not described for Saccharomyces cerevisiae. Catabolite inactivation by addition of glucose was also demonstrated. This particulate enzyme does not respond to activation by the cAMP-dependent protein kinase.
  Biochemistry international 01/1993; 28(4):693-700.
• Article: Specific incorporation of kinetin into eukaryotic and prokaryotic transfer ribonucleic acid molecules.

  J Barciszewski, D Otzen, S I Rattan, B F Clark
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  ABSTRACT: We show that kinetin, a non-natural product with strong cytokinin activity, is incorporated into prokaryotic and eukaryotic tRNAs in the exchange reaction catalysed by a putative tRNA-kinetin transglycosylase. We also show that kinetin is specifically incorporated into E. coli tRNA(Tyr) and most probably at position 37. To our knowledge, this is the first report of a nucleic acid base exchange reaction occurring at this position.
  Biochemistry international 01/1993; 28(5):805-11.
• Article: Interaction between phenylalanine and antisense nucleosides and the effect of pH and salts on the strength of interaction.

  T Cserhati, R Vitti
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  ABSTRACT: The interaction of 12 antisense nucleosides with phenylalanine (Phe), and the effect of pH and salts on the strength of interaction was studied by charge-transfer reversed-phase thin-layer chromatography. Phe significantly decreased the lipophilicity of nucleosides. This effect may be due to the interaction between the more hydrophilic Phe and the more lipophilic nucleosides, resulting in charge-transfer complexes of moderate lipophilicity. The relative strength of interaction was the weakest in acidic and the strongest in alkaline environment. This finding indicates the partially or entirely hydrophilic character of the interaction. Salts influenced to a lesser extent the interaction, their effect depended both on the concentration and on the type of cation. The relatively low impact of salts on the strength of interaction suggests that other than hydrophilic forces are involved in the Phe - antisense nucleoside interaction.
  Biochemistry international 01/1993; 28(5):929-38.
• Article: Hammett rho sigma correlation for the inhibition by indoles of coniferyl alcohol oxidation catalyzed by cell wall peroxidases.

  M A Ferrer, M A Pedreño, R Muñoz, A Ros Barceló
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  ABSTRACT: The inhibitory effect of indole-3-acetic acid, and of its peroxidase-mediated degradation products of an indole nature, on the oxidation rate of coniferyl alcohol catalyzed by cell wall peroxidases has been studied. The results show that the inhibitory effect of indole-3-acetic acid and indole-3-carbinol may be explained, in part, by their properties as peroxidase substrates. However, I50 values for a series of indole compounds not regarded as peroxidase substrates show a good correlation with the electron-donating or electron-withdrawing nature of the 3-substituents, as judged by the linearity of the Hammett rho sigma plot. These results suggest that although the properties of indole compounds as peroxidase substrates may be responsible, in part, for their inhibitory effects on the peroxidase-mediated oxidation of coniferyl alcohol, the inhibitory effect appears to be mainly determined by the acidity of the imino group of the indole nucleus.
  Biochemistry international 01/1993; 28(5):949-55.
• Article: Effect of inorganic phosphate on hypoxanthine transport in isolated brain microvessels.

  P Cardelli, A Fiori, M C Santulli, F Ceci, C Salerno, M R Savi, V Peresempio, R Strom
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  ABSTRACT: In isolated brain microvessels, used as an in vitro model of the blood-brain barrier, the rate of hypoxanthine uptake was modulated by the presence of inorganic phosphate. A single high-capacity, low-affinity transport system was apparently active in a phosphate-free medium (Vmax = 840 pmol/mg protein/min, Km = 750/uM); in the presence of 10 mM phosphate, there was also a low-capacity, high-affinity system (Vmax = 47 pmol/mg protein/min, Km = 27/uM). The phosphate-dependent component was inactive in the absence of glucose or of Na+ ions, or upon addition of phloretine (but was scarcely affected by 2,4-dinitrophenol). This activity was apparently coupled to the intracellular phosphoribosyltransferase-catalyzed conversion of purines into the corresponding nucleotides: when inorganic phosphate was present in the suspending medium, labeled hypoxanthine was transported with higher efficiency and was readily converted to inosine monophosphate and to other related nucleotides. In the absence of phosphate ions, hypoxanthine was instead metabolized to xanthine and uric acid.
  Biochemistry international 01/1993; 28(5):823-34.
• Article: Purification and properties of chitinase from cabbage.

  C T Chang, H F Lo, C J Wu, H Y Sung
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  ABSTRACT: Chitinase has been purified from the extract of cabbage through successive steps of ammonium sulfate fractionation, chromatofocusing and Sephadex G-75 gel filtration. By these steps, the purity of the enzyme increased by 93.3 fold and the recovery of the enzyme activity was 20%. The purified enzyme had an optimal pH of 5.0, an optimal temperature between 40 to 50 degrees C and a Km of 76 microM for hydrolysis of ethylene glycol chitin. The molecular weight of the enzyme determined from filtration through Sephadex G-75 was 30,000 daltons. Heavy metal ions, Hg2+ (0.5 mM) and Ag+(2.5 mM) significantly inhibited the activity of the enzyme. NBSI1 (1.0 mM), DNFB (0.5 mM) and PMSF (0.5 mM) completely inhibited the activity of the enzyme. The enzyme also showed muramidase activity for hydrolysis of Micrococcus lysodeikticus cell wall. The presence of chitinase in cabbage may function as a defense enzyme against potential pathogens.
  Biochemistry international 01/1993; 28(4):707-15.
• Article: Nucleotide sequence of cDNA for porcine heme oxygenase and its expression in Escherichia coli.

  T Suzuki, M Sato, K Ishikawa, T Yoshida
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  ABSTRACT: The nucleotide sequence of a cDNA for porcine heme oxygenase was determined. The open reading frame encoded a polypeptide of 288 amino acid residues with a molecular mass of 33,074 Da. A prokaryotic expression plasmid carrying porcine heme oxygenase cDNA was constructed and transfected into Escherichia coli cells. The full-length heme oxygenase expressed was localized in the bacterial membranes. Two small-sized heme oxygenases with no membrane-bound properties were also detected, suggesting that in E. coli cells a considerable amount of the enzyme expressed was degraded.
  Biochemistry international 01/1993; 28(5):887-93.
• Article: Comparative effect of fasting on acetoacetate and D-3-hydroxybutyrate metabolism in the newborn chick.

  A Linares, R Diaz, G J Caamaño, F J Gonzalez, E Garcia-Peregrin
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  ABSTRACT: The effect of 24 h fasting on ketone body utilization by three extranervous tissues, liver, duodenum and kidney, was studied in two critical ages of neonatal chick: 4 and 9 days. In 4-day-old chick, plasma concentration of 3-hydroxybutyrate increased about 9-fold after 24 h starvation, while in 9-day-old chick this parameter increased about 23-fold in the same conditions. Hepatic lipogenesis from both precursors sharply decreased by fasting. Changes in the lipogenic activity of duodenum were less patent. However, we have found a clear increase in lipogenesis in chick kidney after 24 h starvation. CO2 production from acetoacetate was higher than that found from hydroxybutyrate. No significant differences in the acetoacetate oxidation to CO2 was observed in any tissue assayed after 24 h fasting. 14C incorporation from ketone bodies into amino acids was clearly decreased in kidney from 9-day-old chick by fasting. In liver and duodenum, acetoacetate incorporation into amino acids was higher than that from hydroxybutyrate.
  Biochemistry international 01/1993; 28(4):683-91.
• Article: Characterisation of genes encoding two novel members of the aldo-keto reductase superfamily.

  B P Dalrymple, J M Peters, T Vuocolo
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  ABSTRACT: The predicted amino acid sequence of the protein encoded by a cDNA clone isolated from the protozoan haemoparasite Babesia bovis has approximately 22% amino acid identity with the Pichia stipitis xylose reductase. There are similar levels of amino acid identity with other members of the aldo-keto reductase superfamily. The identities include many residues highly conserved in the superfamily. However, the amino acid sequence of the B. bovis protein (AKR1) clearly lies outside the cluster of the previously characterized members of the superfamily. A putative protein encoded by a previously undescribed partially characterized open reading frame at the igrA (increased glyphosate resistance) locus of Pseudomonas sp. strain PG2982 also exhibits similarity to AKR1 and the aldo-keto reductases.
  Biochemistry international 01/1993; 28(4):651-7.
• Article: Modulation of trichosanthin antigenicity by coupling to dextran.

  W H Ko, C C Wong, H W Yeung, S C Tam
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  ABSTRACT: Trichosanthin (TCS) is a plant-derived type I ribosome-inactivating protein with a wide spectrum of biological and pharmacological activities. Recently, it was covalently coupled to dextran in order to prolong its half-life in plasma. The major biological activities were generally retained but at lower potency. The immunogenicity of the dextran-trichosanthin (DX-TCS) was compared to that of TCS itself in this study. The results showed that mice immunized with TCS produced 8 times as much TCS-reactive IgE than those immunized with DX-TCS. However, both TCS and DX-TCS immunization produced similar titers of TCS-reactive IgG. A trace of dextran-reactive IgG was detected in mice immunized with DX-TCS. Thus, coupling of TCS to dextran reduced its antigenicity but slightly enhanced that of dextran, and the conjugate elicited less IgE than TCS.
  Biochemistry international 01/1993; 28(4):643-50.
• Article: Inhibition of EGF-induced gastric mucosal calcium channel phosphorylation by ebrotidine.

  B L Slomiany, J Liu, J Piotrowski, A Slomiany
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  ABSTRACT: A gastric mucosal calcium channel-epidermal growth factor (EGF) receptor complex was isolated from solubilized epithelial cell membranes by means of a wheat germ agglutinin affinity. The complex, following reconstitution into phosphatidylcholine vesicles, exhibited active 45Ca2+ uptake as evidence by concentration-dependent response to the calcium channel activator BAY K8644, and the calcium channel antagonist PN200-110. The complex on the addition of EGF and ATP showed an increase in tyrosine phosphorylation of both a 55 and a 170kDa protein, while the vesicles containing the phosphorylated complex displayed a 48% greater 45Ca2+ uptake. The phosphorylation process was inhibited by an anti-ulcer agent, ebrotidine, which also interfered with the binding of EGF to calcium channel protein. The results suggest that ebrotidine protects the cellular integrity from calcium imbalance by modulating the EGF-stimulated gastric mucosal calcium channel activation.
  Biochemistry international 01/1993; 28(4):751-60.
• Article: Interactions of monocrotophos and quinalphos with Anabaena torulosa isolated from rice soil.

  M Bhaskar, C Sreenivasulu, K Venkateswarlu
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  ABSTRACT: The interaction of insecticide combinations of monocrotophos and quinalphos on Anabaena torulosa, by the criteria of absorbance (OD) and packed cell volume (PCV) of the culture, content of chlorophyll a, phycocyanin, carotenoids, total protein, DNA and RNA, heterocyst differentiation and nitrogen fixation, were assessed. In general, monocrotophos and quinalphos, in combination, interacted significantly yielding three different responses viz., additive, antagonistic or synergistic. The nature of the interaction found with OD and PCV was nearly the same for a particular concentration of the insecticides. However, no consistent interaction was observed with respect to carotenoids and phycocyanin. The three types of interaction were noticed for total protein, DNA and RNA. Interestingly, the insecticide combinations at lower concentrations yielded all interaction responses for heterocyst frequency and nitrogenase activity. But, higher concentrations, in combination, resulted in synergism for heterocyst differentiation and nitrogen fixation.
  Biochemistry international 01/1993; 28(5):767-73.
• Article: Comparison of supernatant-and ribosome-bound rat liver tRNA.

  F Varricchio, M Uziel
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  ABSTRACT: Transfer RNAs were separated into a ribosome bound fraction and a supernatant (cytoplasmic) fraction. The nucleoside composition, 2-dimensional PAGE pattern and in vivo labeling were compared. 12 minor nucleosides were identified by HPLC. In general, the minor nucleosides, especially N2-methyl-guanidine and ribothymidine, were higher in the ribosome-bound fraction. The PAGE patterns were similar but there were quantitative and qualitative differences among the smaller spots. In vivo labeling by 32P showed that new tRNA goes preferentially to the ribosome but mixing does occur. The results suggest the existence of two compartments of tRNA.
  Biochemistry international 01/1993; 28(6):1039-44.
• Article: Gonadotropin bioactivities in mouse, hamster, rat and guinea pig pituitaries are largely adsorbed on concanavalin A-sepharose.

  T B Ng, L L Lo, W Y Chan
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  ABSTRACT: The pituitaries of mice, hamsters, guinea pigs and rats were extracted with Tris-Cl buffer and the extracts were chromatographed on Concanavalin A (ConA)-Sepharose into unadsorbed ConA I and adsorbed ConA II fractions. The ConA I fraction was subjected to gel filtration on Sephadex G-100 and fractionated into an unretarded peak and several retarded peaks. The peak with a molecular weight of approximately 40,000 (designated ConAI Sephadex fraction II) was then subjected to ion exchange chromatography on CM-cellulose and fractionated into an unadsorbed CM I and an adsorbed CM II fraction. The ConA II fraction was fractionated by ion exchange chromatography on CM-cellulose into CM I and CM II fractions. The ConA II CM II fraction was the chromatographic fraction which exhibited the highest potency in stimulating testosterone production by isolated rat Leydig cells. Its activity was much higher than the corresponding ConA I Sephadex fraction II CM II fraction which differed chromatographically only by non-adsorption on ConA-Sepharose. The ConA II CM II fraction manifested cross reactivity in a rat luteinizing hormone (LH) radioimmunoassay. The guinea pig pituitary ConA II CM II fraction also cross-reacted in a rat thyroid stimulating hormone radioimmunoassay. The ConA II fractions of hamster and guinea pig pituitary extracts demonstrated follicle stimulating hormone (FSH) activity while the corresponding ConA I fractions did not. The results suggest that the ConA II/ConA II CM II fraction contained most of the FSH and LH activities present in the pituitary extract.
  Biochemistry international 01/1993; 28(6):999-1007.
• Article: Oxidation of cystathionamine and lanthionamine by lentil seedlings amine oxidase.

  G Floris, E Sanjust, A Padiglia, C De Marco
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  ABSTRACT: Cystathionamine and lanthionamine are good substrates for lentil seedlings amine oxidase. One mole of hydrogen peroxide and one mole of ammonia per mole of substrate are produced, indicating that only one amino group is oxidized to aldehyde. The aminoaldehydes so originated undergo cyclization by intramolecular Schiff base formation. The pH optimum for the oxidation of either cystathionamine or lanthionamine is 7.0 in potassium phosphate buffer. The Km values are 0.61 and 0.84 mM respectively, similar to that for cystamine (0.8 mM).
  Biochemistry international 01/1993; 28(6):1109-16.
• Article: Iron-reducing activity of plasma membranes.

  A Berczi, W P Faulk
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  ABSTRACT: Human placental trophoblast plasma membranes were prepared by differential centrifugation and solubilized in nonionic detergent. Transferrin receptors were isolated from the solubilized membranes by affinity chromatography on diferric transferrin-coupled Sepharose 4B. The trophoblast plasma membrane vesicles demonstrated NADH-ferricyanide oxidoreductive activity. However, NADH-Fe(III) oxidoreductive activity was very weak when Fe(III)-ammonium citrate or diferric transferrin was used as electron acceptor in the presence of bathophenanthroline disulfonate as an indicator of the reaction. After solubilization, only NADH-ferricyanide oxidoreduction was recovered. Affinity chromatography-purified transferrin receptors did not exhibit any measurable oxidoreductase activity. Thus, when these receptors are present in plasma membranes they mediate redox reactions, but biochemically isolated receptors do not mediate such reactions. These observation suggest that transferrin receptors in plasma membranes bind diferric transferrin, and, in an undetermined way, facilitate Fe(III) release so that iron reduction can occur.
  Biochemistry international 01/1993; 28(4):577-84.
• Article: In vitro transfer of N-acetylglucosamine to endogenous glycoprotein acceptors catalyzed by the nucleus and the cytoplasmic membranes prepared from L1210 cells.

  J Frot-Coutaz, A Degiuli, R Létoublon, J Vila
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  ABSTRACT: The non-nuclear membranes and the nuclei prepared from L1210 cells catalyze the in vitro transfer of N-acetyl(14C)glucosamine from UDP-N-acetyl(14C)glucosamine to endogenous glycoprotein acceptors. Adequate analysis of these acceptors have demonstrated that the nucleus has its own N-acetylglucosaminyltransferase system that leads to the formation of N-N'-diacetylchitobiosylated proteins.
  Biochemistry international 01/1993; 28(5):905-20.
• Article: Transcriptional regulation of MnSOD by manganese in the liver of manganese-deficient mice and during rat development.

  S Borrello, M E De Leo, T Galeotti
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  ABSTRACT: Evidence is reported that liver manganese deficiency, whether artificially produced by the administration of a Mn-deficient diet, or physiologically occurring in the neonatal life, in mice and rats respectively, causes the down-regulation of the manganese-containing superoxide dismutase at (pre)-transcriptional level. These observations, in addition to previous data concerning Mn-deficiency and the low level of expression of MnSOD in Morris hepatomas, strongly support the role played by the metal ion in the control of the MnSOD by a mechanism of gene activation. While the molecular events taking place in such regulation are not yet identified, the involvement of reactive oxygen species (ROS) as second messengers in the activation of specific transcription factors is suggested.
  Biochemistry international 01/1993; 28(4):595-601.