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PubMedDate not supplied

[Extracellular polysaccharides of saprotrophic mycobacteria and patterns of their formation].

Exocellular polysaccharides were synthesized by ten strains of 7 saprotrophic mycobacterial species in parallel with their growth. The cultures grew and produced polysaccharides more rapidly in a medium with glucose than in a medium with n-hexadecane. The polymers are homogeneous acid heteroglycans of the regular structure. All of them contain glucose and some of them contain hexuronic acid. Galactose, fucose, mannose, ramnose and pyruvic acid are found in some of the polysaccharides. The exoglycans of two mycobacterial species contain mannolactylic acid. Beta-glycosidic linkages prevail in most of the polysaccharides.

Alkanes↗
PubMedDate not supplied

[Effect of salvipholin on the carbohydrate and lipid metabolism in the rat liver in alloxan diabetes].

Peroral administration of salvipholin in a dose of 50 mg/kg to intact male rats (the body weight 180-220 g) had a positive effect on the carbohydrate-lipid metabolism in the liver and blood serum of animals. Administration of the same dose to rats with alloxan diabetes induced a significant decrease in the content of glucose, free fat acids, triglycerides and lysophospholipids of the liver and blood serum. The level of these components has sharply increased after subcutaneous alloxan administration in a dose of 150 mg/kg, the content of glycogen and pyruvic acid being normalized and insulin deficiency removed. These changes are closely related to salvipholin-promoted restoration of phospholipid spectra of the blood serum and liver of experimental animals disturbed under conditions of insulin deficiency. The possible mechanism of the salvipholin action is analyzed.

Animals↗
PubMed2002

CYP119 plus a Sulfolobus tokodaii strain 7 ferredoxin and 2-oxoacid:ferredoxin oxidoreductase constitute a high-temperature cytochrome P450 catalytic system.

The cytochrome P450 superfamily of enzymes catalyzes a broad range of oxidative processes involved in the metabolism of fatty acids, biosynthesis of sterols, and elimination of drugs and xenobiotics. Application of the unique properties of P450 enzymes as fine biocatalysts in biotechnology is limited due to their thermal instability and the requirement for auxiliary electron-donor proteins and cofactors. CYP119, a thermophilic P450 enzyme from Sulfolobus solfataricus, was characterized some time ago, but no high-temperature redox partners have been available for it. Here we report reconstitution of CYP119 with a novel high-temperature electron-donor system consisting of a ferredoxin and 2-oxoacid:ferredoxin oxidoreductase from Sulfolobus tokodaii strain 7 that, unlike all other known P450 electron-donor partners, utilizes coenzyme-A and pyruvic acid rather than NADH or NADPH as the source of electrons. The oxidation of lauric acid by the reconstituted system increased 16-fold as the temperature increased from 25 to 70 degrees C and was functional for more than 30 min at the higher temperature. This first in vitro high-temperature P450 catalytic system is a key step in the development of practical high-temperature monooxygenase systems.

Archaeal Proteins↗
PubMedDate not supplied

Total chemical synthesis of a 27 kDa TASP protein derived from the MscL ion channel of M. tuberculosis by ketoxime-forming ligation.

A 27-kDa TASP protein, T(5)Msc(103-151), that was derived from the cytoplasmic domain (amino acid residues 103-151) of the MscL ion channel of M. tuberculosis was synthesized by ketoxime-forming chemoselective ligation between a template molecule carrying five pyruvic acid groups, and linear channel peptides carrying one aminooxyacetic acid group. Ketoxime-forming ligation provided for highly efficient assembly of this large totally synthetic protein construct with yields >90% with modest excess (1.5x) of the aminooxy peptide. Formation of the desired TASP molecule was confirmed by SDS-PAGE analysis and MALDI mass spectrometry. The effect of template attachment on the structure of the peptides constituting the TASP was assessed by circular dichroism spectroscopy. Attachment of the peptides to the topological template induces predominantly helical secondary structure, whereas an analogous peptide that did not bear an aminooxy group, MscL(103-151), does not exhibit significant secondary structure at pH 7 and is found to be monomeric in concentrations up to 65 microM. This observation can be explained by entropic destabilization of the unfolded state of T(5)Msc(103-151) due to the attachment to the template and the resulting loss of degrees of freedom. Pyruvic acid-based ketoxime-forming chemoselective ligation may thus prove to be a useful tool for the assembly of large, non-native protein constructs and their biophysical study.

Bacterial Proteins↗
PubMed1985

p-Cresol formation by cell-free extracts of Clostridium difficile.

Cell-free extracts of Clostridium difficile were shown to form p-cresol by decarboxylation of p-hydroxyphenylacetic acid. This activity required both high and low molecular weight fractions. The active component of the low molecular weight fraction had properties of an amino acid and could be replaced by serine, threonine or the corresponding alpha keto acids. Pyruvate was shown to function catalytically. Since the high molecular weight fraction was O2-sensitive and since dithionite was as effective as pyruvate with some high molecular weight fractions, the alpha keto acids probably serve as low potential reducing agents in this system. Because of instability, the p-cresol-forming enzyme could not be purified.

Butyrates↗
PubMed1985

Metabolic effects in rats of high oral doses of galactitol, mannitol and xylitol.

The effect of feeding high amounts of polyols on rat metabolism was studied. Adult male rats were fed the basal diet or the same diet to which had been added either galactitol, mannitol or xylitol for 8 wk (final polyol level 200 g/kg diet). Although all three polyols retarded the growth rate of the animals, the polyols were well tolerated. The four experimental groups did not differ significantly (P greater than 0.01) in the following analyses: blood lactic acid and serum transaminases, amylase, lactate dehydrogenase, triglycerides, insulin, glucagon and corticosterone. Compared to rats fed the basal diet, galactitol rats had higher blood hemoglobin levels (P less than 0.01); those fed galactitol or mannitol had lower blood glucose (P less than 0.001 and P less than 0.01, respectively), and those fed mannitol had higher blood pyruvic acid (P less than 0.01). Rats fed any of the polyols had lower serum total cholesterol and liver ascorbic acid (P less than 0.001) than control rats. Rats fed mannitol had higher liver glycogen levels (P less than 0.001) than control rats. Irrespective of the structural differences between the pentitol and the hexitols, a number of common metabolic effects were found. The proposed mechanisms of these effects include 1) the slow absorption and the rapid intraluminal metabolism of the polyols and 2) the similar handling of these polyols in the liver by a dehydrogenase.

Alanine Transaminase↗
PubMed1989

Kinetics of ethanolic fermentation of D-xylose by Klebsiella pneumoniae and its mutants.

The microbial production of ethanol from D-xylose by a new soil isolate of Klebsiella pneumoniae and the mutants K. pneumoniae MB-16 and MB-16-1048 was studied. Kinetic and physiological properties of the mutants were compared with those of the original isolate. The volumetric rates of ethanol formation by mutants MB-16-1048 and MB-16 and the original isolate were 1.58, 0.50, and 0.06 g liter-1 h-1, respectively. The cultivation times of mutants MB-16-1048 and MB-16 were 20 and 18 h, respectively, and that of the original isolate was 118 h. Both the mutants exhibited metabolic similarities with the original isolate. Ethanol was the major end product of fermentation in all three strains. Acetic acid and carbon dioxide were the other two important by-products of fermentation. Pyruvic acid was accumulated in significant proportions as an intermediate. The proportion of pyruvate in the original isolate was 54% of the total D-xylose utilized, whereas for MB-16 and MB-16-1048 the values were about 42 and 22%, respectively. The lower fractions of pyruvate in mutants MB-16 and MB-16-1048 showed up as a 41 and 82% improvement, respectively, over the original isolate in terms of the ethanol yield.

Acetates↗
PubMed1991

A synthesis of acylphosphonic acids and of 1-aminoalkylphosphonic acids: the action of pyruvate dehydrogenase and lactate dehydrogenase on acetylphosphonic acid.

Acylphosphonic acids, R-CO-PO(OH)2, have been synthesized by the steps [formula: see text] of which the last is new and provides a mild method for de-esterifying acylphosphonic acids. Their reductive amination gives a simple way of making 1-aminoalkylphosphonic acids. Acetylphosphonic acid inhibited NAD+ reduction by pyruvate with the pyruvate dehydrogenases from Escherichia coli and Bacillus stearothermophilus. The inhibition was competitive with pyruvate, with Ki of 6 microM for the E. coli enzyme (pyruvate Km 0.5 mM) and one of 0.4 mM of the B. stearothermophilus enzyme (pyruvate Km 0.1 mM). Acetylphosphonate and its monomethyl ester are substates for pig heart lactate dehydrogenase, with Km values of 15 mM and 10 mM respectively (pyruvate Km 0.05 mM) and specificity constants one thousandth that for pyruvate.

Acetaldehyde↗
PubMed1983

The substrate-mediated inactivation of the pyruvate dehydrogenase component of the pigeon breast muscle pyruvate dehydrogenase complex.

Incubation of the pyruvate dehydrogenase component isolated from the pigeon breast muscle pyruvate dehydrogenase complex with Mg2+, thiamine pyrophosphate and low concentrations of pyruvic acid in the absence of electron acceptors results in irreversible time-dependent inactivation of the enzyme. The rate of the enzyme inactivation is markedly decreased in the presence of high concentrations of pyruvate; in this case acetoin and acetolactate are detected in the reaction mixture. The enzyme activity is stabilized when the artificial electron acceptor, 2,6-dichlorophenolindophenol, is present in the reaction mixture. The substrate-mediated inactivation of the enzyme is accompanied by incorporation of the 2-[14C]-substrate fragment and labelled thiamine pyrophosphate into the protein fraction. The enzyme reactivation by neutral hydroxylamine and the protective effect of dithiothreitol suggest that the SH-group(s) may be involved in the substrate-mediated inactivation of pyruvate dehydrogenase.

Animals↗
PubMed1985

Structural studies of a mannitol teichoic acid from the cell wall of bacterium N.C.T.C. 9742.

Degradative and n.m.r.-spectroscopic studies have been carried out on a novel mannitol teichoic acid extracted from the cell wall of bacterium N.C.T.C. 9742, for which the name Brevibacterium iodinum has been proposed. The backbone of the polymer is a poly(D-mannitol phosphate) containing 1----6 phosphodiester linkages. In most residues, pyruvic acid is acetal-linked to positions 4 and 5 of the mannitol. About half of the mannitol residues carry a beta-D-glucopyranosyl substituent at position 2. The glucosylmannitol was isolated and thoroughly characterized. At least 24 products were detected by ion-exchange chromatography and paper electrophoresis after alkaline hydrolysis of the polymer. Not all of these products could be identified. The main mechanistic pathways for depolymerization by the cleavage of phosphodiester linkages during alkaline hydrolysis involved (a) participation by the 2-hydroxy group and a cyclic phosphodiester intermediate (leading to a series of mannitol-based products) and (b) participation by the 3-hydroxy group in the cyclization of mannitol (leading to a series of products based on 1,4-anhydromannitol). The presence of glycerol phosphates in hydrolysates could be ascribed either to a linkage unit or to a separate glycerol teichoic acid. The mannitol teichoic acid was absent from the cell walls of Brevibacterium linens and Brevibacterium epidermis (one strain of each was examined).

Biopolymers↗
PubMed2001

Comparison of methyl rotation axis order parameters derived from model-free analyses of (2)H and (13)C longitudinal and transverse relaxation rates measured in the same protein sample.

Recombinant HIV-1 protease was obtained from bacteria grown on a 98% D(2)O medium containing 3-(13)C pyruvic acid as the sole source of (13)C and (1)H. The purified protein is highly deuterated at non-methyl carbons, but contains significant populations of (13)CHD(2) and (13)CH(2)D methyl isotopomers. This pattern of isotope labeling permitted measurements of (1)H and (13)C relaxation rates of (13)CHD(2) isotopomers and (2)H (D) relaxation rates of (13)CH(2)D isotopomers using a single sample. The order parameters S(axis)(2), which characterize the motions of the methyl rotation axes, were derived from model-free analyses of R(1) and R(2) data sets measured for (13)C and (2)H spins. Our primary goal was to compare the S(axis)(2) values derived from the two independent types of data sets to test our understanding of the relaxation mechanisms involved. However, S(axis)(2) values derived from the analyses depend strongly on the geometry of the methyl group, the sizes of the quadrupolar and dipolar couplings, and the effects of bond vibrations and librations on these couplings. Therefore uncertainties in these basic physical parameters complicate comparison of the order parameters. This problem was circumvented by using an experimental relationship, between the methyl quadrupolar, (13)C-(13)C and (13)C-(1)H dipolar couplings, derived from independent measurements of residual static couplings of weakly aligned proteins by Ottiger and Bax (J. Am. Chem. Soc. 1999, 121, 4690-4695) and Mittermaier and Kay (J. Am. Chem. Soc. 1999, 121, 10608-10613). This approach placed a tight experimental restraint on the values of the (2)H quadrupolar and (13)C-(1)H dipolar interactions and greatly facilitated the accurate comparison of the relative values of the order parameters. When applied to our data this approach yielded satisfactory agreement between the S(axis)(2) values derived from the (13)C and (2)H data sets.

Amino Acids↗
PubMed2000

Full structure of the O-specific polysaccharide of Proteus mirabilis O24 containing 3,4-O-[(S)-1-carboxyethylidene]-D-galactose.

The structure of a neutral polysaccharide isolated by degradation with dilute acetic acid of the lipopolysaccharide (LPS) of P. mirabilis O24 has been determined recently [E. Literacka et al., FEBS Lett., 456 (1999) 227-231]. Further studies of this LPS using alkaline degradation and hydrolysis at pH 4.5 showed that the polysaccharide chain includes an acetal-linked pyruvic acid residue, which is removed completely during delipidation with acetic acid. A revision using 1H and 13C NMR spectroscopy and methylation analysis resulted in determination of the following full structure of the repeating unit of the O-specific polysaccharide: carbohydrate sequence [see text] where D-Gal3,4(S-Pyr) is 3,4-O-[(S)-1-carboxyethylidene]-D-galactose.

Acetic Acid↗
PubMed1991

Reactions of 4-aryl-1-hydrazinophthalazines with carbonyl compounds.

Reaction of 1-hydrazino-4-phenylphthalazine and 4-benzyl-1-hydrazinophthalazine with different carbonyl compounds are described. With oxalic acid, the two cyclic amidrazones reacted to give 6-aryl-1,2,4-triazolo[3,4-a]phthalazines. Reaction with diethyl oxalate, however, afforded the corresponding 7-aryl-3,4-dioxo-1,2,4-triazino[3,4-a]phthalazines. With pyruvic acid, ethyl pyruvate, or methyl phenyl glyoxylate the corresponding hydrazones were obtained which were cyclized to 7-aryl-3-methyl or 7-aryl-3-phenyl-1,2,4-triazino[3,4-a]phthalazines, respectively. Whereas the reaction of the two cyclic amidrazones with acetylacetone or ethyl phenyl propiolate gave pyrazole derivatives, their reaction with ethyl acetoacetate gave 6-aryl-3-methyl-1,2,4-triazolo[3,4-a]phthalazines. The results of biological testing of representative examples of the prepared compounds as insecticides and nematicides are reported.

Acetoacetates↗
PubMed1978

[Various metabolic or toxic effects which can result from short term ingestion of sulfurous acid by the rat].

The work reported below was conducted for the purpose of evaluating the toxicity of two levels of potassium metabisulfite on various aspects of metabolism in adult rats. It appears that the two doses do not disturb the activity of acid plasmatic phosphatase. The increase of the pyruvic acid o blood caused for the higher level of sulfite (50 mg/kg/day) is considerably increased for absorption of a diet containing 67% of sugar, and considerably decreased by injection the day before the dosage of 200 microgram thiamine. The highest level (50 mg/kg/day) increased the urinary calcium however same larger quantities of sulfite did not cause any augmentation of fecal calcium. The "creatinine clearance" is not modified, the seric transaminases (G.O.T.-G.P.T.) are not disturbed, moreover, hematologic controls during the five months of experimentation did not show any perturbation.

Acid Phosphatase↗
PubMed1989

Structure of phosphonoglycosphingolipid containing pyruvylated galactose in nerve fibers of Aplysia kurodai.

A phosphonoglycosphingolipid, designated as FGL-IIb, was identified in nerve fibers of Aplysia kurodai by two-dimensional thin layer chromatography (Abe, S., Araki, S., and Satake, M. (1986) Biomed. Res. (Tokyo) 7, 47-51). FGL-IIb was isolated from the nervous system of A. kurodai by Iatrobeads column chromatography using three solvent systems. Pyruvic acid was identified by thin layer chromatography as its 2,4-dinitrophenylhydrazone and established by permethylation studies to be attached as a ketal to O-3 and O-4 of the terminal galactose of the oligosaccharide chain in FGL-IIb. By sugar analysis, permethylation studies, fast atom bombardment-mass spectrometry, and proton magnetic resonance spectrometry, the structure of FGL-IIb was concluded to be [3,4-O-(1-carboxyethylidene)]Gal beta 1----3GalNAc alpha 1----3(Fuc alpha 1----2) (2-aminoethylphosphonyl----6)Gal beta 1----4Glc beta 1----1ceramide. Its major aliphatic components were palmitic acid, octadeca-4-sphingenine and anteisononadeca-4-sphingenine. This is the first report of the occurrence of pyruvylated galactose as a constituent of animal sphingolipid.

Acidic Glycosphingolipids↗
PubMed2000

The cyanide-resistant alternative oxidases from the fungi Pichia stipitis and Neurospora crassa are monomeric and lack regulatory features of the plant enzyme.

Both plant and fungal mitochondria have cyanide-resistant alternative oxidases that use reductant from the mitochondrial ubiquinone pool to reduce oxygen to water in a reaction that conserves no energy for ATP synthesis. The dimeric plant alternative oxidase is relatively inactive when its subunits are linked by a disulfide bond. When this bond is reduced, the enzyme can then be stimulated by its activators, alpha-keto acids. A Cys in the N-terminal section of the protein is responsible for both of these features. We examined the alternative oxidases in mitochondria isolated from two fungi Neurospora crassa and Pichia stipitis for dimeric structure, ability to form an intermolecular disulfide, and sensitivity to alpha-keto acids. Neither of the two fungal alternative oxidases could be covalently linked by diamide, which induces disulfide bond formation between nearby Cys residues, nor could they be cross-linked by a Lys-specific reagent or glutaraldehyde at concentrations which cross-link the plant alternative oxidase dimer completely. Alternative oxidase activity in fungal mitochondria was not stimulated by the alpha-keto acids pyruvate and glyoxylate. Pyruvate did stimulate activity when succinate was the respiratory substrate, but this was not a direct effect on the alternative oxidase. In contrast, added GMP was a strong activator of fungal alternative oxidase activity. Analysis of plant and fungal alternative oxidase protein sequences revealed a unique domain of about 40 amino acids surrounding the regulatory Cys in the plant sequences that is not present in the fungal sequences. This domain may be where dimerization of the plant enzymes occurs. In contrast to plant enzymes, the fungal alternative oxidases studied here are monomeric and their activities are independent of alpha-keto acids.

Acids↗
PubMed1965

Linkage of carbohydrate to hydroxyamino acids in mucopolysaccharides and mucoproteins.

1. Glycosidic linkage of carbohydrate to the primary hydroxyl groups of threonine and serine has been established in human blood-group A and Le(a) substances, bovine submaxillary-gland mucin and human pseudomyxomatous mucin. 2. Treatment of these substances in 0.09n-lithium hydroxide at 100 degrees for 1hr. led to beta-elimination at these glycosidic linkages with the resultant formation of alpha-oxobutyric acid and glycine from threonine linkages, and pyruvic acid from serine linkages. Though most of the threonine was destroyed in every case, about one-third to one-half of the serine residues resisted alkaline cleavage. Such results, indicative of the presence of unbound serine residues, allow, in submaxillary mucin, for a close correlation between the remaining serine, threonine, glutamic acid and aspartic acid and the available sialyl-(2-->6)-N-acetylgalactosamine prosthetic groups. 3. The stoichiometry of the beta-eliminations has been demonstrated for pseudomyxomatous mucin. The alpha-oxo acids were separated and determined as their quinoxalinol derivatives by thin-layer chromatography on silica gel. Reaction at the threonine centres favoured alpha-oxobutyric acid formation (70%, via the intermediary dehydropeptide) over the alternative pathway to glycine (30%). 4. 100% of the hexosamine was destroyed in submaxillary-gland mucin, 85% in pseudomyxomatous mucin and about 60% in the blood-group substances. In the latter cases, the glucosamine/galactosamine ratio was increased from about 4:1 to 8-10:1, suggesting a preferential destruction of galactosamine. Evidence was obtained, however, for a further destruction of hexosamine, in addition to that which could be theoretically attached to peptide at possible known binding sites. 5. The major part of the alkali-resistant hexosamine in the blood-group substances was non-diffusible and was accompanied by the constituent carbohydrates in similar molar proportions to the native materials.

Journal Article↗
PubMed1998

Carbon source utilisation by Bordetella bronchiseptica.

Bordetella bronchiseptica isolates utilised tricarboxylic acid cycle intermediates -- succinate, citrate, alpha-ketoglutarate, fumarate, lactate and oxalo-acetate; the organic acids pyruvate, acetate and lactate; and the amino acids proline, glutamate, glutamine and tyrosine -- as sole sources of carbon and energy. The inability of B. bronchiseptica isolates, representing the three phase types and from different animal hosts, to utilise carbohydrates and sugar alcohols as sole carbon and energy sources was confirmed and extended. The influence of the carbon substrate on doubling time, piliation, flagellation, motility, capsule production and adherence to mammalian cells was also measured.

Amino Acids↗