المؤلفون: Duncan, R.J.S.¹, Tipton, K.F.¹

المصدر: European Journal of Biochemistry. 1969, Vol. 11 Issue 1, p58-61. 4p.

مصطلحات موضوعية: *LACTATE dehydrogenase, *ISOENZYMES, *OXIDATION, *CHEMICAL reduction, *HYDRATION, *RABBITS

مستخلص: Crystalline rabbit muscle lactate dehydrogenase has been shown to catalyze the oxidation of glyoxylate to oxalate and its reduction to glycollate. Both these reactions have been shown to be catalyzed by all the isoenzymes present. Kinetic constants for both these reactions have been calculated. Oxalate inhibition patterns suggest that glyoxylate may be acting in its hydrated form as a substance for oxidation and in its non-hydrated form as a substrate for reduction. [ABSTRACT FROM AUTHOR]

المؤلفون: Walter Neupert, Bernard Guiard, Christian Klaus, Michael Brunner

المصدر: European journal of biochemistry. 236(3)

مصطلحات موضوعية: Reticulocytes, Mitochondrial processing peptidase, Recombinant Fusion Proteins, Molecular Sequence Data, Restriction Mapping, Saccharomyces cerevisiae, Biology, Mitochondrion, Protein Sorting Signals, Cleavage (embryo), Biochemistry, Mitochondrial Targeting Signal, Protein Structure, Secondary, Scissile bond, Cytochrome b2, Endopeptidases, Animals, Amino Acid Sequence, Protein Precursors, DNA Primers, Sequence Deletion, Base Sequence, L-Lactate Dehydrogenase, Mitochondria, Tetrahydrofolate Dehydrogenase, Oligodeoxyribonucleotides, Mutagenesis, Protein Biosynthesis, Mutagenesis, Site-Directed, L-Lactate Dehydrogenase (Cytochrome), Rabbits, Sequence motif, Signal peptide peptidase, Protein Processing, Post-Translational

الوصف: Determinants in a mitochondrial targeting signal for import and processing were analyzed by introducing deletions into the presequence of cytochrome b2. The matrix targeting signal and the signal recognized by the mitochondrial processing peptidase were found to be separate. The signal for import into the matrix is located at the N-terminus within a stretch of 20 amino acid residues that has the potential to form a positively charged, amphipathic alpha-helix. The mitochondrial processing peptidase cleaves after residue 31 and recognizes a short sequence motif around the scissile bond. In the context of a presequence, the cleavage site is accessible for the processing peptidase. At a different location or in a different context, the cleavage site motif is still specifically recognized but processed with lower efficiency. The matrix targeting signal may help to present the cleavage site motif to the mitochondrial processing peptidase.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b50754d91c83fa679f7c6eb969654a1dTest
https://pubmed.ncbi.nlm.nih.gov/8665906Test

المؤلفون: Marietta Tuena de Gómez-Puyou, Liora Shoshani, Armando Gómez-Puyou, Georgina Garza-Ramos, Alberto Darszon, D. Alejandro Fernández-Velasco, Leticia Nayeli Ramírez Ramírez

المصدر: European journal of biochemistry. 205(2)

مصطلحات موضوعية: Protein Denaturation, Dehydrogenase, Glycerolphosphate Dehydrogenase, Saccharomyces cerevisiae, Biochemistry, Guanidines, Enzyme catalysis, chemistry.chemical_compound, Lactate dehydrogenase, Hexokinase, Animals, Urea, Pyrophosphatases, Guanidine, Chromatography, Aqueous solution, biology, L-Lactate Dehydrogenase, Muscles, Myocardium, Substrate (chemistry), Glyceraldehyde-3-Phosphate Dehydrogenases, Water, Enzyme assay, Enzymes, Enzyme Activation, Isoenzymes, Solutions, Inorganic Pyrophosphatase, Kinetics, chemistry, biology.protein, Solvents, Cattle, Rabbits

الوصف: The effect of urea and guanidine hydrochloride (GdmCl) on the activity of heart lactate dehydrogenase, glycerol-3-phosphate dehydrogenase, hexokinase, inorganic pyrophosphatase, and glyceraldehyde-3-phosphate dehydrogenase was studied in low-water systems. Most of the experiments were made in a system formed with toluene, phospholipids, Triton X-100, and water in a range that varied over 1.0-6.5% (by vol.) [Garza-Ramos, G., Darszon, A., Tuena de Gomez-Puyou, M. & Gomez-Puyou, A. (1990) Biochemistry 29, 751-757]. In such conditions at saturating substrate concentrations, the activity of the enzymes was more than 10 times lower than in all-water media. However the activity of the first four aforementioned enzymes was increased between 4 and 20 times by the denaturants. The most marked activating effect was found with lactate dehydrogenase; with 3.8% (by vol.) water maximal activation was observed with 1.5 M GdmCl (about 20-fold); 4 M urea activated, but to a lower extent. Activation by guanidine thiocyanate was lower than with GdmCl. The activating and inactivating effects of GdmCl on lactate dehydrogenase depended on the amount of water; as the amount of water was increased from 2.0% to 6.0% (by vol.), activation and inactivation took place with progressively lower GdmCl concentrations. When activity was measured as a function of the volume of 1.5 M GdmCl solution, a bell-shaped activation curve was observed. In a low-water system formed with n-octane, hexanol, cetyltrimethylammonium bromide and 3.0% water, a similar activation of lactate dehydrogenase by GdmCl and urea was observed. The water solubility diagrams were modified by GdmCl and urea, and this could reflect on enzyme activity. However, from a comparison of denaturant concentrations on the activity of the enzymes studied, it would seem that, independently of their effect on the characteristics of the low-water systems, denaturants bring about activation through their known mechanism of action on the protein. It is suggested that the effect of denaturants is due to the release of constraints in enzyme catalysis imposed by a low-water environment.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::4c0de7a9ad9189282c6656afa6b1890eTest
https://pubmed.ncbi.nlm.nih.gov/1315269Test

المؤلفون: Tetsuya Yomo, Hirosuke Okada, Itaru Urabe

المصدر: European journal of biochemistry. 203(3)

مصطلحات موضوعية: Oxidase test, L-Lactate Dehydrogenase, Stereochemistry, Chemistry, Muscles, Tetrazolium Salts, Dehydrogenase, NAD, Biochemistry, Turnover number, Mixed Function Oxygenases, Oxygen, chemistry.chemical_compound, Kinetics, Thiazoles, Glycerol-3-phosphate dehydrogenase, Lactate dehydrogenase, Chromatography, Gel, Moiety, Animals, Phenazines, NAD+ kinase, Steady state (chemistry), Rabbits, Mathematics

الوصف: 5-Ethylphenazine-lactate-dehydrogenase-NAD+ conjugate (EP(+)-LDH-NAD+) was prepared by linking poly(ethylene glycol)-bound 5-ethylphenazine and poly(ethylene glycol)-bound NAD+ to lactate dehydrogenase. The average number of the ethylphenazine moieties bound per molecule of enzyme subunit was 0.46, and that of the NAD+ moieties was 0.32. This conjugate is a semisynthetic enzyme having lactate oxidase activity using oxygen or 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) as an electron acceptor; to make such conjugates seems to be a general method for artificially converting a dehydrogenase into an oxidase. When the concentration of oxygen or MTT is varied, the oxidase activity fits the Michaelis-Menten equation with the following kinetic constants: for the reaction system with oxygen, the turnover number per subunit is 2.3 min-1 and Km for oxygen is 1.91 mM; and for the system with MTT, the turnover number is 0.25 min-1 and Km for MTT is 0.076 mM. At the initial steady state of the oxidase reaction, only 2.1% of the NAD+ moieties of the conjugate are in the free state (i.e. not bound in the coenzyme-binding site of the lactate dehydrogenase moiety) and the rest are hidden in the coenzyme site; almost all the NAD+ moieties are in the reduced state. The apparent intramolecular rate constant for the reaction between a free NADH moiety and an oxidized ethylphenazine moiety is 2.3 s-1 and 2.1 s-1 for the systems with oxygen and with MTT, respectively. The apparent effective concentration of the free NADH moiety for the ethylphenazine moiety is 5.5 microM and is much smaller than that (0.34 mM) of the ethylphenazine moiety for the free NADH moiety; this difference is due to the effect of hiding the NADH moiety in the binding site, as the hidden NADH moiety cannot react with the ethylphenazine moiety.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::49a7ce7d5645c814e4ffc3dcb881448bTest
https://pubmed.ncbi.nlm.nih.gov/1735437Test

المؤلفون: Hitoshi Nakamoto, Sanjit Kumer Roy, Tetsuo Hiyama

المصدر: European journal of biochemistry. 262(2)

مصطلحات موضوعية: Blotting, Western, Molecular Sequence Data, Biology, Cyanobacteria, Biochemistry, HSPA4, chemistry.chemical_compound, Biopolymers, Bacterial Proteins, Malate Dehydrogenase, Heat shock protein, Lactate dehydrogenase, Animals, Amino Acid Sequence, Heat shock, Peptide sequence, Chromatography, High Pressure Liquid, Heat-Shock Proteins, Gel electrophoresis, chemistry.chemical_classification, HSPA14, Sequence Homology, Amino Acid, Molecular biology, Crystallins, Recombinant Proteins, Amino acid, chemistry, Rabbits, Heat-Shock Response

الوصف: A 16-kDa protein, one of the major proteins that accumulates upon heat-shock treatment in the thermophilic cyanobacterium Synechococcus vulcanus, was purified to apparent homogeneity. The N-terminal and internal amino acid sequences of the protein exhibited a homology to the alpha-crystallin-related, small heat shock proteins from other organisms. The protein was designated HspA. Size-exclusion chromatography and nondenaturing gel electrophoresis demonstrated that HspA formed a large homo-oligomer consisting of 24 subunits. It prevented the aggregation of porcine malic dehydrogenase at 45 degrees C and 50 degrees C and citrate synthase at 50 degrees C. The activity of the malic dehydrogenase, however, was not protected under these heat-shock conditions or reactivated after a shift in temperature from 45 or 50 degrees C to 21 degrees C. HspA was able to enhance the refolding of chemically denatured rabbit muscle lactate dehydrogenase in an ATP-independent manner. A homologue to the 16-kDa protein was also found to be induced upon heat-shock treatment in the mesophilic cyanobacterium Synechocystis sp. PCC 6803.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::394fd8ce68179293aa195e9a058963f5Test
https://pubmed.ncbi.nlm.nih.gov/10336625Test

المؤلفون: Chanchal DasGupta, Biswadip Das, Aloke Kumar Bera, Subrata Chattopadhyay

المصدر: European journal of biochemistry. 235(3)

مصطلحات موضوعية: Male, Protein Denaturation, Protein Folding, Biology, Glucosephosphate Dehydrogenase, medicine.disease_cause, Biochemistry, Ribosome, Catalysis, 23S ribosomal RNA, medicine, Escherichia coli, Animals, Triticum, 50S, chemistry.chemical_classification, L-Lactate Dehydrogenase, Ribosomal RNA, 16S ribosomal RNA, Molecular biology, Protein tertiary structure, Rats, Kinetics, RNA, Ribosomal, 23S, Enzyme, chemistry, Liver, Nucleic Acid Conformation, Female, Rabbits, Ribosomes

الوصف: Ribosomes from a number of prokaryotic and eukaryotic sources (e.g., Escherichia coli, wheat germ and rat liver) can refold a number of enzymes which are denatured with guanidine/HCl prior to incubation with ribosomes. In this report, we present our observations on the refolding of denatured lactate dehydro-genase from rabbit muscle and glucose-6-phosphate dehydrogenase from baker's yeast by ribosomes from E. coli, wheat germ and rat liver, The protein-folding activity of E. coli, ribosomes was found to be present in 50s particles and in 23S rRNA. The 30S particle or 16S rRNA did not show any protein-folding activity. The protein-folding activity of 23S rRNA may depend on its tertiary conformation. Loss of tertiary structure, by incubation with low concentrations of EDTA, inhibited the protein-folding activity of 23S rRNA. This low concentration of EDTA had no effect on folding of the denatured enzymes by themselves.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::731784eb07d819db9ac85e45d295d984Test
https://pubmed.ncbi.nlm.nih.gov/8654409Test

المؤلفون: Edi Gabellieri, Giovanni B. Strambini

المصدر: European journal of biochemistry. 221(1)

مصطلحات موضوعية: L-Iditol 2-Dehydrogenase, Sorbitol dehydrogenase, Globular protein, Stereochemistry, Protein Conformation, Swine, Dehydrogenase, Glycerolphosphate Dehydrogenase, Biochemistry, Cofactor, Protein structure, Escherichia coli, Animals, Alcohol dehydrogenase, chemistry.chemical_classification, Quenching (fluorescence), biology, L-Lactate Dehydrogenase, Chemistry, Tryptophan, Alcohol Dehydrogenase, Temperature, Glyceraldehyde-3-Phosphate Dehydrogenases, Solutions, Luminescent Measurements, biology.protein, Rabbits

الوصف: Random collisions between macromolecules lead to dynamic associations (lengthy encounters) that in principle could affect their conformation and, in the case of enzymes, their binding and catalytic properties. Exploiting the unique sensitivity of the phosphorescence lifetime, tau, of Trp to the internal flexibility of globular proteins we probed the perturbations induced in the structure of the coenzyme-binding domain of alcohol dehydrogenase (LADH) and glyceraldehyde-3-phosphate dehydrogenase (GraPDH) by the presence in solution of other dehydrogenases and of functionally unrelated proteins. With Trp314 of LADH, the results emphasize that while tau is not affected by the concentration of LADH itself, the addition of micromolar quantities of other proteins causes a distinct reduction in it. From the linear increase of 1/tau with protein concentration one obtains values for the apparent second-order Stern-Volmer rate constant that range between 2-200 x 10(3) M-1 s-1, decreasing 2-3-fold when ternary complexes of LADH with NADH or NAD+ and inhibitors are involved. Similar effects were observed with Trp310 of GraPDH except that with sorbitol dehydrogenase as perturbant the increase of 1/tau is hyperbolic and governed by an apparent dissociation constant of about 1 microM. Finally, glycerol-3-phosphate dehydrogenase, the strongest perturber of both LADH and GraPDH, has either no effect on lactic dehydrogenase from pig heart or induces a moderate lengthening of the triplet lifetime of the rabbit muscle enzyme. Because Stern-Volmer behavior is typical also of diffusion-mediated quenching reactions, a parallel investigation with cysteine, cystine and N-acetyl-tryptophanamide demonstrated that among potential, protein-associated, quenching moieties namely, -SH, -S-S- and indole groups, only the latter has rate constants approaching the magnitude of protein perturbants. Since considerable evidence rules out the predominance of such quenching reactions, these findings confirm a subtle form of communication between protein molecules in solution. The lack of specificity and the similar effects between dehydrogenases with right and wrong stereospecificity for direct coenzyme transfer suggests that the perturbations monitored are unrelated to this function.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::68c519e770775bf6da34cdda22255505Test
https://pubmed.ncbi.nlm.nih.gov/8168551Test

المؤلفون: Peter Friedrich, János Hajdu, Ferenc Bartha

المصدر: European Journal of Biochemistry. 68:373-383

مصطلحات موضوعية: Macromolecular Substances, Protein Conformation, Swine, Stereochemistry, Biochemistry, chemistry.chemical_compound, Tetramer, Fructose-Bisphosphate Aldolase, Lactate dehydrogenase, Animals, Bifunctional, Binding Sites, L-Lactate Dehydrogenase, biology, Muscles, Aldolase A, Actins, Symmetry (physics), Isoenzymes, Kinetics, Electrophoresis, Chain length, Dimethyl Suberimidate, chemistry, Reagent, biology.protein, Rabbits, Mathematics, Protein Binding

الوصف: A method based upon the principle that unlike domains of bonding are reflected in different re-activities and distribution of residues that can be crosslinked, has been elaborated for the determination of symmetry of oligomeric proteins. The derivation of theoretical curves for the prediction of crosslinking patterns of tetramers produced by reaction with a bifunctional reagent and subsequent sodium-dodecylsulphate-gel electrophoretic analysis is presented. Based upon the theory the symmetry properties of a tetramer, to the extent whether it is an isologous or heterologous associationn, can be deduced by a simple calculation. Crosslinking patterns obtained with rabbit muscle aldolase and pig muscle lactate dehydrogenase after treatment with a series of diimidoesters of increasing chain length are evaluated and shown to be consistent with the expectations for isologous tetramers. From the patterns obtained with the various reagents the distances between lysyl residues located nearest to each other in different subunits in the two proteins could also be determined.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::18aa73a08c02c67c0c4e4204432a5450Test
https://doi.org/10.1111/j.1432-1033.1976.tb10824.xTest

المؤلفون: Hans-Dietrich Lüdemann, Rainer Jaenicke, Gerhard Schmid

المصدر: European Journal of Biochemistry. 86:219-224

مصطلحات موضوعية: L-Lactate Dehydrogenase, Lability, Muscles, Kinetics, Hydrostatic pressure, Inorganic chemistry, Substrate (chemistry), chemistry.chemical_element, Biochemistry, Oxygen, Dithiothreitol, Enzyme Activation, Enzyme activator, chemistry.chemical_compound, chemistry, Lactate dehydrogenase, Pressure, Biophysics, Animals, Rabbits, Sulfhydryl Compounds, Mathematics

الوصف: Lactate dehydrogenase from rabbit skeletal muscle in the presence of substrate exhibits irreversible deactivation at hydrostatic pressures beyond 1 kbar [Schmid, G., Ludemann, H.-D. & Jaenicke, R. (1975) Biophys. Chem. 3, 90-98]. In the absence of substrate and coenzyme the lability towards pressure is enhanced. The pH dependence of the effect and its inhibition by SH-protecting agents suggest the oxidation of sulfhydryl groups to be involved in the mechanism of deactivation. Partial deactivation observed at pH 5.5-7.0 becomes complete in the range of the intrinsic pK of cysteine; addition of dithiothreitol and/or EDTA protects the enzyme from complete deactivation, and leads to the residual enzymatic activity observed at pH 7.0. Incubation of the enzyme with dithiothreitol after pressure deactivation at pH 8.5 causes partial reactivation. From pressure-dependent measurements of the kinetics of deactivation an activation volume of deltaVnot equal to = -285 +/- 30 cm3 . mol-1 is calculated, which exceeds numerical data reported for typical reactions in organic chemistry. Therefore, the assumption can be made that the oxidation of sulfhydryl groups is connected with structural changes in the enzyme in the rate-determining step of the deactivation. The proposed mechanism may contribute to the toxicity of oxygen towards bacteria under high hydrostatic pressure.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::04c4748fbee84772c70b7e49f9081dd5Test
https://doi.org/10.1111/j.1432-1033.1978.tb12302.xTest

المؤلفون: Jean-Pierre Samama, Michael G. Rossmann, Nicole Marchal-Rosenheimer, Jean-Francois Beiellmann

المصدر: European Journal of Biochemistry. 120:563-569

مصطلحات موضوعية: chemistry.chemical_classification, Binding Sites, L-Lactate Dehydrogenase, Nicotinamide, biology, Stereochemistry, Coenzymes, Active site, NAD, Biochemistry, Cofactor, Kinetics, chemistry.chemical_compound, Species Specificity, chemistry, Dogfish, Lactate dehydrogenase, biology.protein, Animals, Moiety, Cattle, Rabbits, Pyridinium, NAD+ kinase, Thioamide

الوصف: The kinetic properties of 18 NAD+ analogues, with alterations to the nicotinamide moiety, have been studied with respect to dogfish M4, rabbit M4 and beef H4 lactate dehydrogenases. The size of the groups present at C-3 of the pyridinium can be increased quite extensively without loss of coenzyme activity. Groups tested were thioamide, methyl, ethyl, diazoketone and chloroacetyl. Substitutions at positions C-4 and C-5 prevent proper positioning for hydride transfer and can hinder binding to the enzyme. The kinetic properties of pyridine-adenine dinucleotide and its 3-iodo derivative reveal the bidning role of the amide at C-3 whereas 3-cyanopyridine-adenine dinculeotide is a strong inhibitor.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fd7a6e8cbdc59bfc1de9ee6a417bafa3Test
https://doi.org/10.1111/j.1432-1033.1981.tb05737.xTest