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PubMed1987

Use of p-aminobenzoic acid and tritiated cyanoborohydride for the detection of pyruvoyl residues in proteins.

A procedure for the detection of covalently bound pyruvic acid in purified proteins or in crude extracts is described. The dialyzed sample is first treated with sodium cyanoborohydride to reduce any Schiff bases present and then incubated with p-aminobenzoic acid and sodium [3H]cyanoborohydride. Derivatized proteins are visualized by fluorography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel slices containing the labeled proteins are hydrolyzed, and, after removal of polyacrylic acid, the hydrolysate is subjected to ion-exchange high-performance liquid chromatography. The presence of pyruvic acid is established by the detection of a tritiated, 280-nm absorbing compound with a retention time corresponding to that of synthetic N-(p-carboxyphenyl)alanine. The procedure is capable of detecting protein-bound pyruvic acid in the picomolar range and is easily modified to screen for other covalently bound keto acids.

4-Aminobenzoic Acid↗
PubMed1996

Sleeping time after phenobarbital treatment and the brain levels of gamma-aminobutyric acid and phenobarbital at the regaining of righting response point in ethionine-induced liver-disordered mice.

The mechanism of prolongation of sleeping (anesthesia) time after phenobarbital (PB) treatment was assessed in mice with ethionine (ET)-induced liver disorders (ET-treated group). The brain gamma-aminobutyric acid (GABA), glutamic acid (GLU), lactic acid (LA), and pyruvic acid (PA) levels were significantly higher in the ET-treated group than the control group. The ET-treated group showed an abnormal neurotransmission and a decrease in energy metabolism. After administration of PB (175 mg/kg, i.p.), sleeping time and the brain GABA, GLU, LA, PA, and PB levels at the awakening point were compared between ET-treated and control groups. Sleeping time in the ET-treated group was two times longer than that in the control group. At the awakening point, the brain GABA and LA levels in the ET-treated and control groups and the PA level in the ET-treated group were significantly lower than those without PB treatment; and the GLU level in the ET-treated group was significantly higher than that without PB treatment. The brain concentrations of PB in both groups remained the same for seven hr after PB treatment. There was no difference in the brain PB concentration between the two groups at the awakening point, although the ET-treated group showed impairment of excretion of PB at 18 hr of PB treatment. In conclusion, awakening is not directly correlated with a decrease in PB in the brain, but rather to changes in the brain GABA, GLU, and other substances, and an inhibition of the neurotransmission and decreased energy metabolism in the brain are considered to be involved in the prolongation of PB-induced sleeping time in the ET-treated mice.

Anesthesia↗
PubMed1986

Effect of alpha-ketobutyrate on palmitic acid and pyruvate metabolism in isolated rat hepatocytes.

alpha-Ketobutyrate, an intermediate in the catabolism of threonine and methionine, is metabolized to CO2 and propionyl-CoA. Recent studies have suggested that propionyl-CoA may interfere with normal hepatic oxidative metabolism. Based on these observations, the present study examined the effect of alpha-ketobutyrate on palmitic acid and pyruvate metabolism in hepatocytes isolated from fed rats. alpha-Ketobutyrate (10 mM) inhibited the oxidation of palmitic acid by 34%. In the presence of 10 mM carnitine, the inhibition of palmitic acid oxidation by alpha-ketobutyrate was reduced to 21%. These observations are similar to those previously reported using propionate as an inhibitor of fatty acid oxidation, suggesting that propionyl-CoA may be responsible for the inhibition. alpha-Ketobutyrate (10 mM) inhibited 14CO2 generation from [14C]pyruvate by more than 75%. This inhibition was quantitatively larger than seen with equal concentrations of propionate. Carnitine (10 mM) had no effect on the inhibition of pyruvate oxidation by alpha-ketobutyrate despite the generation of large amounts of propionylcarnitine during the incubation. alpha-Ketobutyrate inhibited [14C]glucose formation from [14C]pyruvate by more than 60%. This contrasted to a 30% inhibition caused by propionate. These results suggest that alpha-ketobutyrate inhibits hepatic pyruvate metabolism by a mechanism independent of propionyl-CoA formation. The present study demonstrates that tissue accumulation of alpha-ketobutyrate may lead to disruption of normal cellular metabolism. Additionally, the production of propionyl-CoA from alpha-ketobutyrate is associated with increased generation of propionylcarnitine. These observations provide further evidence that organic acid accumulation associated with a number of disease states may result in interference with normal hepatic metabolism and increased carnitine requirements.

Acyl Coenzyme A↗
PubMed1976

Studies on the influence of fatty acids on pyruvate dehydrogenase interconversion in rat-liver mitochondria.

1. The effect of fatty acids on the interconversion of pyruvate dehydrogenase between its active (nonphosphorylated) and inactive (phosphorylated) forms was measured in rat liver mitochondria respiring in state 3 with pyruvate plus malate and 2-oxoglutarate plus malate and during state 4 to state 3 transition in the presence of different substrates. The content of intramitochondrial adenine nucleotides was determined in the parallel experiments. 2. Decrease of the intramitochondrial ATP/ADP ratio with propionate and its increase with palmitoyl-L-carnitine in state 3 is accompanied by a shift of the steady-state of the pyruvate dehydrogenase system towards the active or the inactive form, respectively. 3. Transition from the high energy state (state4) to the active respiration (state3) in mitochondria oxidizing 2-oxoglutarate or plamitoyl-L-carnitine causes an increase of the amount of the active form of pyruvate dehydrogenase due to the decrease of ATP/ADP ratio in the matrix. 4. No change in ATP/ADP ratio can be observed in the presence of octanoate in mitochondria oxidizing pyruvate or 2-oxoglutarate in state 3 or during state 4 to state 3 transition. Simultanelusly, no significant change in phosphorylation state of pyruvate dehydrogenase occurs and a low amount of the enzyme in the active form is present with octanoate or octanoate plus 2-oxoglutarate. Pyruvate abolishes this effect of octanoate and shifts the steady-state of pyruvate dehydrogenase system towards the active form. 5. These results indicate that fatty acids influence the interconversion of pyruvate dehydrogenase mainly by changing intramitochondrial ATP/ADP ratio. However, the comparison of the steady-state level of the pyruvate dehydrogenase system in the presence of different substrates in various metabolic conditions provides some evidence that accumulation of acetyl-CoA and high level of NADH may promote the phosphorylation of pyruvate dehydrogenase. 6. Pyruvate exerts its protective effect against phosphorylation of pyruvate dehydrogenase in the presence of fatty acids of short, medium or long chain in a manner which depends on its concentration. It is suggested that in isolated mitochondria pyruvate counteracts the effect of acetyl-CoA and NADH on pyruvate dehydrogenase kinase.

Adenosine Diphosphate↗
PubMed1981

Elevation of blood keto acids in cerebrocortical necrosis.

Values of various alpha-keto acids in whole blood were determined from cases of cerebrocortical necrosis (CCN), a thiamine deficiency disease, and were compared with those from normal animals. Thiamine pyrophosphate is an essential cofactor in the decarboxylation of many alpha-keto acids and this was reflected in elevated values not only of pyruvic acid but of glyoxylic, alpha-keto glutaric, phenyl pyruvic and hydroxyphenyl pyruvic acids in the CCN cases.

Animals↗
PubMed1987

[Biochemical factors in the pathogenesis of autonomic crises].

Twenty-six neurotic patients with psychovegetative syndromes and eight healthy subjects were studied for the following vegetative and biological parameters: heart rate, respiration rate, skin galvanic reflex (SGR), and blood levels of lactic acid (LA) and pyruvic acid (PA). The examination was carried out under normal conditions and after exercise. It was found that the patients were more reactive to exercise as compared to the healthy subjects with regard to both vegetative (respiration rate, heart rate) and biochemical parameters (LA, PA). The maximal reactivity was observed to be associated with a considerable degree of emotional stress revealed by the test of comprehensive study of personality.

Adult↗
PubMed2004

Structures of cell wall teichoic acids of Brevibacterium iodinum VKM Ac-2106.

Structures of two cell wall teichoic acids of Brevibacterium iodinum VKM Ac-2106 were studied. The structure of mannitol teichoic acid described earlier was mainly confirmed. This polymer is 1,6-poly(mannitol phosphate) bearing beta-D-glucopyranosyl residues at the C-2 of mannitol and pyruvic acid residues at the C-4 and C-5. The absolute configurations of D-mannitol and S-pyruvic acid were found. The following distinctions from the earlier described structure were found: unsubstituted 1,6-poly(mannitol phosphate) residues and residues substituted only by beta-D-glucopyranosyl at the C-2 of mannitol but unsubstituted by pyruvic acid are present in the chain. The structure of glycerol teichoic acid present in the cell wall as a minor component (approximately 7%) is also described. This acid is identified as 1,3-poly(glycerol phosphate) substituted at the C-2 of glycerol by 2-acetamido-2-deoxy-alpha-D-galactopyranosyl residues bearing R-pyruvic acid residues at the C-4 and C-6 of galactose. This polymer is for the first time described in the cell wall of Gram-positive bacteria.

Brevibacterium↗
PubMed1987

[Changes in organic acids in plasma and cerebrospinal fluid in cerebral infarct].

Seventeen patients with recent cerebral infarction were included in the study. The general condition of the patients was evaluated within 3 days after the incidence (rating 1) and 7-9 days after the incidence (rating 2) using a clinical rating scale for internal, psychiatric and neurological findings. The statistical evaluation showed a clinical improvement of the score of 32%. The extent of the brain lesions was determined by cranial computed tomography. Routine analysis of the cerebrospinal fluid included determination of protein, cell count, cell type, glucose, lactic acid, and hemoglobin. In addition, spinal fluid and serum concentration of pyruvic acid, citric acid, fumaric acid, alpha-ketoglutaric acid and alpha-keto-beta-methylvaleric acid (3-MKV) were determined at the two rating times. CSF and serum values of fumaric acid, 3-MKV and pyruvic acid correlated at rating 1, while at rating 2 a correlation existed only for fumaric acid. A trend analysis infarction - postinfarction period showed the concentration of all metabolites to decrease significantly. This is interpreted as a reconstitution of the initially disturbed blood brain barrier function.

Aged↗
PubMed1990

Seasonal cyclicity in carbohydrate metabolism parameters in the European bison, Bison bonasus L.

1. In 197 European bison divided into four groups (Group 1, 0-3-year-old males; Group 2, 0-3-year-old females; Group 3, mature bulls, over 3 years old; Group 4, mature cows, over 3 years old) seasonal changes in the level of lactic and pyruvic acids, glucose and alkaline reserve were studied. 2. Seasonal cyclicity was found only in lactic acid levels in all groups. 3. In the pyruvic acid level cyclicity was found only in males. 4. In the glucose level cyclicity was found only in mature cows. 5. In alkaline reserve cyclicity was found only in mature bison. 6. Six out of 9 acrophases of cyclic indices occurred in the period from the second half of August until mid-December, i.e. before the winter time.

Alkalies↗
PubMed1981

Thyroid hormone synthesis in thyroglobulin. The mechanism of the coupling reaction.

[U-14C]Tyrosine-labeled noniodinated hog thyroglobulin was iodinated enzymatically and nonenzymatically (iodine, iodide-chloramine-T, pH 7.4, or iodine monochloride, pH 8.1). This led to similar levels of iodine incorporation as well as of thyroid hormone synthesis. Iodine monochloride at pH 5.5 formed "hormonogenic" iodotyrosine residues, but no hormone residues. The latter were formed when the iodinated thyroglobulin was brought to pH 8.5 and then treated with horseradish peroxidase and glucose-glucose oxidase in the absence of iodide and iodine monochloride. Enzymatic hydrolysates contained labeled hormone and pyruvic acid; acid hydrolysates labeled thyronine and acetic acid. (Treatment with acid converts hormone to thyronine and pyruvic to acetic acid.) After borohydride treatment, labeled alanine was present instead of pyruvic or acetic acid. The pyruvic acid/hormone, acetic acid/thyronine, alanine/hormone, and alanine/thyronine molar ratios always were 1, independently of the method of iodination. The "coupling reaction" consists of an oxidation step and nonoxidative coupling and decomposition steps. The oxidation step may be either enzymatic or nonenzymatic. The decomposition step always leads to 1 dehydroalanine residue for each hormone residue synthesized. (Dehydroalanine residues appear in the various hydrolysates as acetic acid, pyruvic acid, and alanine, respectively.) Since proper alignment of 2 iodotyrosine residues is a prerequisite for coupling, a model is proposed according to which oxidation of hormonogenic iodotyrosine residues leads to a charge transfer complex which is the same zwitterion-biradical resonance hybrid no matter whether it resulted from a free radical (enzymatic) or an ionic (nonenzymatic) oxidation.

Animals↗
PubMed2002

Crystallization and some properties of D-lactate dehydrogenase from Staphylococcus sp. LDH-1.

Staphylococcus sp. LDH-1 isolated as a high producer of lactate dehydrogenase grew well under anaerobic conditions and produced a large amount of D-lactate dehydrogenase (D-LDH), but not L-LDH. After purification of this D-LDH, some properties were revealed. The enzyme catalyzed the reversible reduction of 2-oxo acids into D-2-hydroxy acids, but not into L-2-hydroxy acids. The K(m) values for 2-oxo acids were much smaller than those for D-2-hydroxy acids, and the V(max) values for 2-oxo acids were much greater than those for D-2-hydroxy acids. The equilibrium constants for the reaction of the reductions of pyruvic acid to D-lactic acid and of 2-oxobutyric acid to D-2-hydroxy-n-butyric acid were 270 and 360, respectively. The enzyme was stable between pH 5.5 and 8.5, while the optimum pH for pyruvic acid and D-lactic acid was pH 5.0 and 8.2, respectively. It was therefore concluded that the D-LDH from Staphylococcus sp. LDH-1 is available as enzyme for an assay of pyruvic acid and for the production of D-2-hydroxy acids.

Journal Article↗
PubMed1984

Relations between fatty acid synthesis, pyruvate concentration and cell concentration of suspensions of isolated rat hepatocytes.

The cell concentration of suspensions of isolated rat hepatocytes affects both the rate of pyruvate accumulation in the incubation medium and the rate of fatty acid synthesis. At low cell concentrations pyruvate accumulation is directly related to the cell concentration but levels off at higher concentrations even when maximum pyruvate concentrations in the medium are not yet reached. The rate of fatty acid synthesis in the 30-60-min incubation interval is proportional to the cell concentration. In contrast, the rate of fatty acid synthesis during the 0-30-min incubation period decreases with increasing cell concentrations and subsequently becomes independent of the cell concentration.

Animals↗
PubMed1997

[The effect of polarizing mixture KIG (potassium + insulin + glucose) on some metabolites of glucose transformation in patients with ischemic stroke during the earliest period of illness].

The purpose of the study was to investigate the effect of polarizing mixture on the level of lactic and pyruvic acids in blood and cerebro-spinal fluid of patients with acute ischaemic stroke in the earliest phase of illness. The investigation was done in 20 patients with completed stroke and 16 with TIA, which were treated with polarizing mixture. The diminution of the level of lactic acid in blood and cerebro-spinal fluid near to normal values was found in patients with completed stroke after treatment with intravenous infusions of polarizing mixture, but the level of pyruvic acid in body fluids mentioned above was increased in unsteady way after this treatment. The concentrations of lactic and pyruvic acids in blood of patients with TIA after treatment with polarizing mixture in the first twenty-four hours of illness were insignificantly elevated in comparison with the control group. The significant diminution of the lactate/pyruvate ratio in cerebro-spinal fluid found in patients with completed stroke treated with polarizing mixture may be an index of reduction of lactic acid cedemogenic effect on the brain.

Aged↗
PubMed1985

Synthesis of pyruvate-1-11C as a radiopharmaceutical for tumor imaging.

Pyruvate-1-11C was prepared enzymatically by the exchange reaction of 11CO2 with the carboxyl group of pyruvic acid using pyruvate-ferredoxin oxidoreductase from Clostridium butyricum. 11C-Labeled pyruvate was purified by sublimation in specially made glassware. The radiochemical yield of pure pyruvate-1-11C was 80% 35 min after the end of bombardment. The distribution of 11C in tumor-bearing rabbits after an i.v. injection of pyruvate-1-11C was observed using a gamma camera. In contrast to normal organs, the tumor was positively visualized. We also conducted a number of successful clinical studies. A case of brain tumor which exhibited a positive image on positron-emission tomography (PET) using pyruvate-1-11C is presented.

Animals↗