Temat: biosynthesis - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Evidence for the presence of the Kennedy and Bremer- Greenberg pathways in Caenorhabditis elegans.
Autorzy:: Lochnit, Günter
Geyer, Rudolf
Powiązania:: https://bibliotekanauki.pl/articles/1043417.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: nematodes; choline metabolism; phosphatidylcholine biosynthesis
Opis:: Nematodes were found to synthesize phosphorylcholine-containing molecules not present in higher organisms, i.e. phosphorylcholine-substituted glycosphingolipids and (glyco)proteins. Investigations on the biosynthesis of these structures provided first biochemical evidence for the presence of the Kennedy and Bremer-Greenberg pathways in the model organism Caenorhabditis elegans.
Źródło:: Acta Biochimica Polonica; 2003, 50, 4; 1239-1243
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The new aspects of aminoacyl-tRNA synthetases.
Autorzy:: Szymański, Maciej
Deniziak, Marzanna
Barciszewski, Jan
Powiązania:: https://bibliotekanauki.pl/articles/1044333.pdf
Data publikacji:: 2000
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: tRNA
aminoacylation
protein biosynthesis
aminoacyl-tRNA synthetases
Opis:: Aminoacyl-tRNA synthetases (AARS) are essential proteins found in all living organisms. They form a diverse group of enzymes that ensure the fidelity of transfer of genetic information from the DNA into the protein. AARS catalyse the attachment of amino acids to transfer RNAs and thereby establish the rules of the genetic code by virtue of matching the nucleotide triplet of the anticodon with its cognate amino acid. Here we summarise the effects of recent studies on this interesting family of multifunctional enzymes.
Źródło:: Acta Biochimica Polonica; 2000, 47, 3; 821-834
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Modification of non-protein thiols contents in transgenic tobacco plants producing bacterial enzymes of cysteine biosynthesis pathway.
Autorzy:: Liszewska, Frantz
Błaszczyk, Anna
Sirko, Agnieszka
Powiązania:: https://bibliotekanauki.pl/articles/1044094.pdf
Data publikacji:: 2001
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: transgenic tobacco
cysteine biosynthesis
thiols
sulfur metabolism
Opis:: Conditions of achieving the maximal accumulation of sulfhydryl metabolites in the leaves of tobacco were explored. Simultaneous production of bacterial O-acetylserine (thiol)-lyase and serine acetyltransferase resulted in the increased thiols contents as compared to single transformants and controls. However, leaf discs feeding experiments differently affected thiols concentration in different plant groups and suggested that the most promising strategy to obtain plants with a high level of non-protein thiol-containing compounds might be sulfate feeding to plants overproducing serine acetyltransferase.Formation of cysteine from sulfide and O-acetyl-L-serine (OAS) is catalyzed by O-acetylserine (thiol)-lyase (OAS-TL) (EC 4.2.99.8) while OAS is synthesized by serine acetyltransferase (SAT) from acetyl-coenzyme A and serine. Molecular interactions between SAT and OAS-TL are involved in the regulation of the enzymatic activities of these proteins in bacteria (Mino et al., 2000) and in plants (Bogdanova & Hell, 1997; Droux et al., 1998). Experiments with Escherichia coli enzymes clearly indicated that OAS-TL activity was reduced to 30% in a complex (Mino et al., 2000). Similarly, a very dramatic decrease of the catalytic activity of OAS-TL bound in a complex has been reported for the plant enzymes (Droux et al., 1998). On the other hand, the bienzyme complex formation stabilizes bacterial SAT (Mino et al., 2000) and increases the apparent affinity for the substrates of plant SAT (Droux et al., 1998). The stability of the complex is negatively affected by OAS and positively by sulfide (Droux et al., 1998). Bacterial SAT is feedback regulated by cysteine, however, no relationship seems to exist between the complex formation and SAT sensitivity to this inhibition (Mino et al., 2000).Both enzymes, SAT and OAS-TL, are located in three compartments of the plant cell: the cytosol, chloroplasts and mitochondria. Different isoforms of these enzymes are in a different way regulated by sulfur nutrition (Nakamura et al., 1999; Takahashi et al., 1997; Warrilow & Hawkesford, 1998). The feedback regulation by L-cysteine of various isoforms of plant SAT has recently been studied (Inoue et al., 1999; Noji et al., 1998). According to the model proposed, the only role of the chloroplastic and mitochondrial isoforms (that are insensitive to the feedback inhibition) would be the production of OAS for cysteine biosynthesis. The cysteine-sensitive cystosolic isoform of SAT would, according to this model, have two roles: (i) OAS production for cysteine biosynthesis in the cystosol and (ii) control of OAS pool for regulatory purposes. The second postulated function is tightly connected with the fact that OAS acts as a positive regulator of genes whose expression is affected by sulfur status (Saito, 2000).Glutathione, the main low-molecular-mass thiol-containing compound in the plant cell, has multiple functions, including involvement in responses to various environmental stresses and maintenance of the redox homeostasis (Foyer & Rennenberg, 2000). Under non-stressing conditions the majority of glutathione is maintained in the reduced form (GSH) and its concentration is determined mainly by the rate of biosynthesis. GSH is produced from cysteine, glutamate and glycine in two steps catalyzed by γ-glutamylcysteinyl synthetase (γ-ECS) and glutathione synthetase (GS), respectively (Noctor et al., 1998). The biosynthesis and accumulation of GSH has been shown to depend on (i) the activity of γ-ECS, (ii) the availability of cysteine, and (iii) the light-dependent formation of glycine through the photorespiratory pathway (Foyer & Rennenberg, 2000).The main aim of this study was to identify the optimal conditions for the maximal accumulation of non-protein sulfhydryl metabolites in plant leaves. The transgenic tobacco plants with cytosolic production of bacterial enzymes of the cysteine biosynthesis pathway, SAT and OAS-TL, were obtained and analyzed for the transgenes expression. Additionally, leaf discs of either single or double transformants, as well as of control plants, were assayed for the thiol contents upon incubation in solutions of various compounds expected to have an influence on sulfur metabolism.
Źródło:: Acta Biochimica Polonica; 2001, 48, 3; 647-656
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: EPR study of thylakoid membrane dynamics in mutants of the carotenoid biosynthesis pathway of Synechocystis sp. PCC6803
Autorzy:: Kłodawska, Kinga
Malec, Przemysław
Kis, Mihály
Gombos, Zoltán
Strzałka, Kazimierz
Powiązania:: https://bibliotekanauki.pl/articles/1039783.pdf
Data publikacji:: 2012
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: cyanobacteria
carotenoid biosynthesis enzymes
spin labels
lipid desaturases
Opis:: EPR spectroscopy using 5-doxylstearic acid (5-SASL) and 16-doxylstearic acid (16-SASL) spin probes was used to study the fluidity of thylakoid membranes. These were isolated from wild type Synechocystis and from several mutants in genes encoding selected enzymes of the carotenoid biosynthesis pathway and/or acyl-lipid desaturases. Cyanobacteria were cultivated at 25°C and 35°C under different light regimes: photoautotrophically (PAG) and/or in light-activated heterotrophic conditions (LAHG). The relative fluidity of membranes was estimated from EPR spectra based on the empirical outermost splitting parameter in a temperature range from 15°C to 40°C. Our findings demonstrate that in native thylakoid membranes the elimination of xanthophylls decreased fluidity in the inner membrane region under optimal growth conditions (25°C) and increased it under sublethal heat stress (35°C). This indicated that the overall fluidity of native photosynthetic membranes in cyanobacteria may be influenced by the ratio of polar to non-polar carotenoid pools under different environmental conditions.
Źródło:: Acta Biochimica Polonica; 2012, 59, 1; 87-90
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Characterization of two aminotransferases from Candida albicans
Autorzy:: Rząd, Kamila
Gabriel, Iwona
Powiązania:: https://bibliotekanauki.pl/articles/1038942.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: l-lysine biosynthesis
aminoadipate aminotransferase
aromatic aminotransferase
Candida albicans
Opis:: Aminoadipate aminotransferase (AmAA) is an enzyme of α-aminoadipate pathway (AAP) for l-lysine biosynthesis. AmAA may also participated in biosynthesis or degradation of aromatic amino acids and in d-tryptophan based pigment production. The AAP is unique for fungal microorganisms. Enzymes involved in this pathway have specific structures and properties. These features can be used as potential molecular markers. Enzymes catalyzing reactions of l-lysine biosynthesis in Candida albicans may also become new targets for antifungal chemotherapy. Search of the NCBI database resulted in identification of two putative aminoadipate aminotransferase genes from Candida albicans: ARO8 (ORFs 19.2098 and 19.9645) and YER152C (ORFs 19.1180 and 19.8771). ARO8 from C. albicans exhibits 53% identity to ARO8 from S. cerevisiae, while YER152C exhibits 30% identity to ARO8 and 45% to YER152C from S. cerevisiae. We amplified two genes from the C. albicans genome: ARO8 and YER152C. Both were cloned and expressed as His-tagged fusion proteins in E. coli. The purified Aro8CHp gene product revealed aromatic and α-aminoadipate aminotransferase activity. Basic molecular properties of the purified protein were determined. We obtained catalytic parameters of Aro8CHp with aromatic amino acids and aminoadipate (AA) (Km(L-Phe) 0.05±0.003 mM, Km(L-Tyr) 0.1±0.008 mM, Km(L-AA) 0.02±0.006 mM) and confirmed the enzyme broad substrate spectrum. The assays also demonstrated that this enzyme may use 2-oxoadipate and 2-oxoglutarate (2-OG) as amino acceptors. Aro8-CHp exhibited pH optima range of 8, which is similar to AmAA from S. cerevisiae. Our results also indicate that CaYer152Cp has a possible role only in aromatic amino acids degradation, in contrast to CaAro8CHp.
Źródło:: Acta Biochimica Polonica; 2015, 62, 4; 903-912
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Hem12, an enzyme of heme biosynthesis pathway, is monoubiquitinated by Rsp5 ubiquitin ligase in yeast cells
Autorzy:: Chelstowska, Anna
Jastrzebska, Zaneta
Kaminska, Joanna
Sadurska, Anna
Plochocka, Danuta
Rytka, Joanna
Zoladek, Teresa
Powiązania:: https://bibliotekanauki.pl/articles/1038993.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: yeast
heme biosynthesis
Hem12
ubiquitination
Rsp5 ligase
protein degradation
Opis:: Heme biosynthesis pathway is conserved in yeast and humans and hem12 yeast mutants mimic porphyria cutanea tarda (PCT), a hereditary human disease caused by mutations in the UROD gene. Even though mutations in other genes also affect UROD activity and predispose to sporadic PCT, the regulation of UROD is unknown. Here, we used yeast as a model to study regulation of Hem12 by ubiquitination and involvement of Rsp5 ubiquitin ligase in this process. We found that Hem12 is monoubiquitinated in vivo by Rsp5. Hem12 contains three conserved lysine residues located on the protein surface that can potentially be ubiquitinated and lysine K8 is close to the 36-LPEY-39 (PY) motif which binds WW domains of the Rsp5 ligase. The hem12-K8A mutation results in a defect in cell growth on a glycerol medium at 38°C but it does not affect the level of Hem12. The hem12-L36A,P37A mutations which destroy the PY motif result in a more profound growth defect on both, glycerol and glucose-containing media. However, after several passages on the glucose medium, the hem12-L36A,P37A cells adapt to the growth medium owing to higher expression of hem12-L36A,P37A gene and higher stability of the mutant Hem12-L36A,P37A protein. The Hem12 protein is downregulated upon heat stress in a Rsp5-independent way. Thus, Rsp5-dependent Hem12 monoubiquitination is important for its functioning, but not required for its degradation. Since Rsp5 has homologs among the Nedd4 family of ubiquitin ligases in humans, a similar regulation by ubiquitination might be also important for functioning of the human UROD.
Źródło:: Acta Biochimica Polonica; 2015, 62, 3; 509-515
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Isolation of Nicotiana plumbaginifolia cDNAs encoding isoforms of serine acetyltransferase and O-acetylserine (thiol) lyase in a yeast two-hybrid system with Escherichia coli cysE and cysK genes as baits.
Autorzy:: Liszewska, Frantz
Gaganidze, Dali
Sirko, Agnieszka
Powiązania:: https://bibliotekanauki.pl/articles/1041469.pdf
Data publikacji:: 2005
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: yeast two-hybrid system
genome walking
cysteine biosynthesis
cDNA cloning
tobacco
Opis:: We applied the yeast two-hybrid system for screening of a cDNA library of Nicotiana plumbaginifolia for clones encoding plant proteins interacting with two proteins of Escherichia coli: serine acetyltransferase (SAT, the product of cysE gene) and O-acetylserine (thiol) lyase A, also termed cysteine synthase (OASTL-A, the product of cysK gene). Two plant cDNA clones were identified when using the cysE gene as a bait. These clones encode a probable cytosolic isoform of OASTL and an organellar isoform of SAT, respectively, as indicated by evolutionary trees. The second clone, encoding SAT, was identified independently also as a "prey" when using cysK as a bait. Our results reveal the possibility of applying the two-hybrid system for cloning of plant cDNAs encoding enzymes of the cysteine synthase complex in the two-hybrid system. Additionally, using genome walking sequences located upstream of the sat1 cDNA were identified. Subsequently, in silico analyses were performed aiming towards identification of the potential signal peptide and possible location of the deduced mature protein encoded by sat1.
Źródło:: Acta Biochimica Polonica; 2005, 52, 1; 117-128
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Difference in the late ergosterol biosynthesis between yeast spheroplasts and intact cells
Autorzy:: Ferrante, Terenzio
Viola, Franca
Balliano, Gianni
Oliaro-Bosso, Simonetta
Powiązania:: https://bibliotekanauki.pl/articles/1038831.pdf
Data publikacji:: 2016
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: yeast cell wall
spheroplasts
late sterol biosynthesis
engineered yeast strains
Erg27p
Erg7p
Opis:: A comparative study on post-squalene sterol synthesis in intact yeast cells and spheroplasts was carried out with strains from three genera (Saccharomyces cerevisiae, Schizosaccharomyces pombe, Pichia pastoris) as well as with engineered S. cerevisiae cells altered in regard to the late ergosterol synthesis pathway. A common outcome of incubation experiments with radioactive acetate was that in intact cells the metabolic pathway flows till its specific end product (ergosterol and its precursor, depending on the enzyme deficiency), whereas in spheroplasts the pathway was stalled some step upstream. For example, in spheroplasts from wt strains, non-cyclic triterpenes squalene and oxidosqualene accumulated as though the metabolic path was kept from producing steroid-shaped molecules different from the end product. Accumulation of non-cyclic triterpenes was observed also in spheroplasts from S. cerevisiae cells lacking 3-ketosteroid reductase activity, an enzyme belonging to the C4-demethylase complex. When production of cyclic triterpenes was compromised by loss or poor functionality of oxidosqualene cyclase (EC 5.4.99.7), the difference between intact cells and spheroplasts was still remarkable, yet limited to the different oxido/dioxidosqualene ratio. The characteristics of spheroplasts as non-proliferating cells may partially explain the observed differences in post-squalene pathway from intact cells. We cannot say if the difference in metabolic pathways in spheroplasts and intact cells is a rule. We think, however, that it is worthwhile to search for an answer, as a wider picture of the points where the metabolic pathways are stalled in spheroplasts could provide original ideas about the metabolic network in yeast.
Źródło:: Acta Biochimica Polonica; 2016, 63, 2; 371-375
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Xanthine, xanthosine and its nucleotides: solution structures of neutral and ionic forms, and relevance to substrate properties in various enzyme systems and metabolic pathways.
Autorzy:: Kulikowska, Ewa
Kierdaszuk, Borys
Shugar, David
Powiązania:: https://bibliotekanauki.pl/articles/1043286.pdf
Data publikacji:: 2004
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: enzyme reactions
prototropic tautomerism
xanthine
caffeine biosynthesis
metabolic pathways
G proteins
base pairing
xanthosine
acid/base properties
nucleotides
Opis:: The 6-oxopurine xanthine (Xan, neutral form 2,6-diketopurine) differs from the corresponding 6-oxopurines guanine (Gua) and hypoxanthine (Hyp) in that, at physiological pH, it consists of a ≈ 1:1 equilibrium mixture of the neutral and monoanionic forms, the latter due to ionization of N(3)-H, in striking contrast to dissociation of the N(1)-H in both Gua and Hyp at higher pH. In xanthosine (Xao) and its nucleotides the xanthine ring is predominantly, or exclusively, a similar monoanion at physiological pH. The foregoing has, somewhat surprisingly, been widely overlooked in studies on the properties of these compounds in various enzyme systems and metabolic pathways, including, amongst others, xanthine oxidase, purine phosphoribosyltransferases, IMP dehydrogenases, purine nucleoside phosphorylases, nucleoside hydrolases, the enzymes involved in the biosynthesis of caffeine, the development of xanthine nucleotide-directed G proteins, the pharmacological properties of alkylxanthines. We here review the acid/base properties of xanthine, its nucleosides and nucleotides, their N-alkyl derivatives and other analogues, and their relevance to studies on the foregoing. Included also is a survey of the pH-dependent helical forms of polyxanthylic acid, poly(X), its ability to form helical complexes with a broad range of other synthetic homopolynucleotides, the base pairing properties of xanthine in synthetic oligonucleotides, and in damaged DNA, as well as enzymes involved in circumventing the existence of xanthine in natural DNA.
Źródło:: Acta Biochimica Polonica; 2004, 51, 2; 493-531
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: The cell-free protein biosynthesis - applications and analysis of the system.
Autorzy:: Lamla, Thorsten
Mammeri, Kerstin
Erdmann, Volker
Powiązania:: https://bibliotekanauki.pl/articles/1044140.pdf
Data publikacji:: 2001
Wydawca:: Polskie Towarzystwo Biochemiczne
Tematy:: in vitro protein biosynthesis
ribosome display
2D-gel elctrophoresis
His-tag and function
in vitro evolution of proteins
Strep-tag affinity peptide
Opis:: The in vitro protein biosynthesis has the potentials to become a powerful technology for biochemical research. Beside the determination of structure and function the in vitro evolution of proteins is also of great interest. The system described was used to produce bovine heart fatty acid binding protein (FABP) and bacterial chloramphenicol acetyltransferase (CAT) with and without fusion of the Strep-tag II affinity peptide. The proteins were purified after and during protein biosynthesis by using a StrepTactin Sepharose matrix. No significant influence of the Strep-tag and the conditions during the affinity chromatography on maturation or activity of the protein was observed. The in vitro evolution of proteins is feasible by means of ribosome display. The selection of a specific mRNA coding for a shortened FABP with a N-terminal His-tag via the accompanying protein property was shown. Goal of the selection was to bind the FABP via the His-tag on Ni(II)-IDA-agarose. After nine cycles of transcription, translation, affinity selection and RT-PCR the protein with the His-tag could be enriched 108-fold. In order to correlate a possible relationship between changes in protein population and biological function studies were initiated in which 2-dimensional protein patterns of the total in vitro system were compared after 0 and 2 h reaction time. The very interesting findings are that a number of proteins disappear, while others are newly formed during protein synthesis.
Źródło:: Acta Biochimica Polonica; 2001, 48, 2; 453-465
0001-527X
Pojawia się w:: Acta Biochimica Polonica
Dostawca treści:: Biblioteka Nauki

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