The synthesis of amino acids from 2,3-dihydrofuran DL-ornithine, DL-proline, and DL-alpha-amino-delta-hydroxyvaleric acid.
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Amino Acids↗
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Results for “VALERIC ACID”
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[Studies on the oxidation reaction of octanol-2 with nitric acid by infrared spectroscopy].
In this paper, the reaction process of oxidation of octanol-2 with nitric acid has been studied by IR spectroscopy. It is found that the main components of non-sapoifiable matter are different in different oxidation degrees. The relation between oxidation products and the amount of nitric acid are investigated,the reaction mechanism has also been studied. Experimental results show that the oxidation process of octanol-2 is as follows: first, octanol-2 is oxidated to octanone-2, or to nitrate, nitrite and nitrile copmpounds, then these compounds are reoxidated to caproic acid in the meantime some by-products, such as valeric, enanthic acids are also found in oxidated products.
English Abstract↗
Assessment of rumen processes by selected-ion-flow-tube mass spectrometric analysis of rumen gases.
This work investigated the potential to use measurement of the concentration of certain gases in the rumen headspace to gain information about rumen processes and as a potential diagnostic tool. We used new equipment (selected-ion-flow-tube mass spectrometer) that allows rapid and precise analysis of many of the gases present in a sample. Samples of rumen headspace gas and corresponding samples of rumen liquor were taken from three lactating cows, prepared with rumen fistulae, at intervals after receiving their morning feed allocation (grass silage and concentrates). Hydrogen sulfide, methyl sulfide, and dimethyl sulfide, were the predominant gases that were measured in the rumen headspace by this technique. The concentrations of these sulfur compounds declined over the interval after feeding, mirroring ammonia concentrations measured in rumen liquor, reflecting their common dependence on the fermentation of sulfur amino acids. Ammonia concentrations in rumen headspace gas varied in the opposite direction to the concentration of ammonia in rumen liquor and likely depend more on the pH of rumen liquor. Consideration of the pKa of ammonia suggests that ammonia concentrations in rumen gas will be very low below pH 6, representing a useful diagnostic for subacute ruminal acidosis. Low concentrations of volatile fatty acids were detected in rumen gas. The molar proportions of volatile fatty acids were similar in gas and liquor samples, with rumen gas containing slightly less acetic acid and disproportionately more valeric and caproic acids.
Acidosis↗
Isotopic acetate and isovalerate in the synthesis of ergosterol by Neurospora.
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Acetates↗
Study of the toxic effect of short- and medium-chain monocarboxylic acids on the growth of Saccharomyces cerevisiae using the CO2-auxo-accelerostat fermentation system.
The effect of aliphatic monocarboxylic acids (formic, acetic, propionic, valeric, octanoic and decanoic acids) on the growth and metabolic activity of Saccharomyces cerevisiae S288C was studied, using continuous cultivation method - CO(2)-auxo-accelerostat with smooth increase in the concentration of added monocarboxylic acids. Slow increase in the concentration of these acids resulted in the rapid decrease in the growth yield (Y(ATP)) and specific growth rate (micro), however, the specific ATP production rate (Q(ATP)) increased or stayed almost constant. On the other hand, Q(ATP) decreased if the concentration of formic, acetic or decanoic acids was increased rapidly. The toxic effect of aliphatic monocarboxylic acids on the growth of S. cerevisiae was characterized and quantified from the respective dose-effect curves as the IC(50) value (mM) using two different endpoints: a decrease of 50% in the specific growth rate (IC(50 micro)) and a decrease of 50% in the growth yield based on ATP production (IC(50YATP)). The concentrations of formic, acetic, propionic, valeric, octanoic and decanoic acids causing the 50% reduction in the specific growth rate (IC(50 micro)) were, respectively, 18.1, 47.1, 33.6, 2.3, 0.16 and 0.07 mM. The IC(50 micro) values were notably lower (up to 5-fold) in case of a more rapid increase in the concentration of acid in the medium. The results of the CO(2)-auxo-accelerostat experiments show that the toxic effect depends not only on the nature of the monocarboxylic acid (lipophilicity) but also on the rate at which its concentration changes in the growth environment.
Adaptation, Physiological↗
Relative fatty acid composition of lecithin during postmenopausal replacement therapy--a comparison between ethinyl estradiol and estradiol valerate.
The relative fatty acid composition of serum lecithin was followed in groups of women during postmenopausal replacement therapy. The effects of estradiol valerate and ethinyl estradiol in two different doses, and the modulating influence of various progestogens and antiestrogens were compared. Unopposed estrogen treatment enhanced liver lecithin synthesis along pathway I, i.e. reduced the amount of stearic acid and increased the amount of palmitic acid. The effect was clearly dose-dependent and even the low dose of 10 micrograms of ethinyl estradiol was more potent than 2 mg of estradiol valerate. No qualitative difference between the two estrogens was recorded. The sequential addition of the antiestrogen tamoxifen significantly reduced the influence of ethinyl estradiol. Liver lecithin synthesis along pathway I may be stimulated by all estrogens and not only by 17C-alkylated compounds. The prostaglandin precursors, dihomogammalinolenic and arachidonic acid, showed a seemingly dose-dependent increase during estrogen treatment. The comparatively weaker effects of estradiol valerate on lipid metabolism should make this non-alkylated estrogen the first choice in clinical practice.
Adult↗
Leakage of cellular material from Thiobacillus ferrooxidans in the presence of organic acids.
Thiobacillus ferroodixans cells released varying amounts of iron, phosphate, sugar, ribonucleic acid, deoxyribonucleic acid, and substances that absorbed light at both 260 and 280 nm, when exposed to 10(-2) to 10(-1) M concentrations of these organic acids: propionic, butyric, valeric, hexanoic, and oxalacetic. These acids also retarded iron oxidation by the cells. Electron microscope observation of cells after exposure to the organic acids showed varying degrees of cell envelope disruption, suggesting that the mode of inhibition of autotrophic iron oxidation in the cell involves interference with the function of the cell envelope, possibly the cell membrane.
Acids↗
Production of esters by Staphylococci.
The ability of resting cells and extracellular concentrates of Staphylococci to synthesize ethyl esters was studied in the presence of ethanol and short chain acids considered individually. All the strains synthesized ethyl esters, S. warneri was the highest producer and S. carnosus the lowest. Resting cells esterified preferentially butanoic acid, extracellular concentrates esterified butanoic, valeric and hexanoic acids. Acetic, decanoic and branched acids were poorly esterified. The activity of the extracellular concentrates with ethanol and butanoic acid was not modified by the pH (pH 5.5 or 7.0); but it was decreased at a temperature of 14 degrees C compared to 24 degrees C. For the resting cells it was the opposite, the activity was inhibited by acid pH and was not influenced by the temperatures. So the Staphylococci could produce esters during sausage manufacture.
Analysis of Variance↗
Effect of pH on fecal recovery of energy derived from volatile fatty acids.
We assessed the effect of pH on volatilization of short-chain fatty acids during lyophilization. Acetic, propionic, valeric, and butyric acids were added to a fecal homogenate in amounts sufficient to raise the energy density by 18-27%. Fecal homogenate samples were either acidified (pH 2.8-3.2), alkalinized (pH 7.9-8.7), or left unchanged (4.0-4.8) prior to lyophilization and subsequent bomb calorimetry. Alkalinizing the fecal samples prevented the 20% loss of energy derived from each of these volatile fatty acids observed in samples either acidified or without pH adjustment. These data suggest that in energy balance studies involving subjects with active colonic fermentation, fecal samples should be alkalinized prior to lyophilization and bomb calorimetry.
Calorimetry↗
Serum levels of short-chain fatty acids in cirrhosis and hepatic coma.
Short-chain fatty acids cause reversible coma in animals and may contribute to the pathogenesis of the hepatic coma in humans. The concentrations of short-chain fatty acids in peripheral venous blood were significantly elevated in 15 patients with hepatic encephalopathy caused by cirrhosis (362 +/- 83 mumol/L; mean +/- S.E.M.) compared with 17 cirrhotic patients without encephalopathy (178 +/- 57 mumol/L) and 11 normal individuals (60 +/- 8 mumol/L). However, no correlation between the depth of coma and the level of short-chain fatty acids was found after repetitive measurements in the coma group. Compared with normal individuals, all short-chain fatty acids, except valerate, were elevated in patients with hepatic encephalopathy, whereas only the concentrations of isobutyrate and isovalerate were significantly elevated in cirrhotic patients without encephalopathy. The concentrations of short-chain fatty acids in 21 nonencephalopathic cirrhotic patients who underwent catheterization were equally distributed in the aorta (187 +/- 56 mumol/L), the hepatic vein (212 +/- 75 mumol/L), the azygos vein (140 +/- 37 mumol/L) and the renal vein (135 +/- 43 mumol/L) compared with peripheral venous blood (178 +/- 57 mumol/L). This study does not support the idea that short-chain fatty acids are of major importance in the pathogenesis of hepatic coma in patients with cirrhosis.
Adult↗
Anchor-linked intermediates in peptide amide synthesis are caused by dimeric anchors on the solid supports.
Cleavage and kinetic studies have been carried out using commercially obtained H-Tyr(tBu)-5-(4'-aminomethyl-3',5'-dimethoxyphenoxy)valeric acid-TentaGelS (H-Tyr(tBu)-4-ADPV-TentaGelS) and H-Tyr (tBu)-4-ADPV-Ala-aminomethyl-resin (H-Tyr(tBu)-4-ADPV-AM-resin) prepared from commercially available resin and loaded with commercially available Fmoc-4-ADPV-OH amide anchor. Cleavage with pure trifluoroacetic acid (TFA) gave the intermediate H-Tyr-4-ADPV-NH2, which was then degraded to H-Tyr-NH2, and cleavage with TFA/dichloromethane (1:9) yielded H-Tyr-4-ADPV-NH2 which could be isolated in preparative amounts. Cleavage reactions with 15N-labelled H-Ala-4-ADPV-(15N)-Gly-AM-resin yielded the intermediate H-Ala-4-ADPV-NH2, which contained no 15N as demonstrated by 1H-NMR. The analysis of the commercial Fmoc-4-ADPV-OH amide anchor showed the presence of Fmoc-4-ADPV-4-ADPV-OH as an impurity in high amounts. This dimeric anchor molecule is the cause of formation of the anchor-linked peptide intermediate obtained during the cleavage from the resin. The particularly high acid-lability of the amide bond between the two ADPV moieties was utilized to synthesize sidechain and C-terminally 4-ADPV protected pentagastrin on a double-anchor resin, and to cleave it using 5% trifluoroacetic acid in dichloromethane. This method may offer a new way for the synthesis of protected peptide amides with improved solubility to be used in fragment condensation.
Amides↗
Anaphylaxis in chopped guinea pig lung. II. Enhancement of the anaphylactic release of histamine and slow reacting substance by certain dibasic aliphatic acids and inhibition by monobasic fatty acids.
The quantitative release of histamine and slow reacting substance by specific antigen from perfused, chopped, sensitized guinea pig lung has been used to study the opposing effects of monobasic and certain dibasic fatty acids on the anaphylactic reaction. The anaphylactic release of histamine and slow reacting substance is doubled by the addition of 0.5 mM of succinic or maleic acid to the reaction mixture, and enhancement is definite with as little as 0.05 mM of succinic acid. Prolonged preincubation of the tissue with the dibasic acids is not required, for 60 to 90 per cent of maximal enhancement is apparent when the antigen is added to the tissue only 10 seconds after succinic or maleic acid. The increased histamine release is not due to a qualitative change in the time course of histamine release, is not the result of increased histamine formation, and cannot be attributed to an effect on the tricarboxylic acid cycle. The enhancement seems to be due to potentiation of some step activated by the antigen-antibody interaction and common to both the release of histamine and slow reacting substance. The structural configuration required for a dibasic acid to enhance the anaphylactic reaction in guinea pig lung is quite specific; the carboxyl groups should be separated by a two carbon chain, and must be free or fixed in the cis position. The monobasic fatty acids from valeric to dodecanoic inhibit the anaphylactic release of histamine, and the concentration needed to produce 50 per cent inhibition decreases with increasing chain length. The introduction of a polar group, amino or carboxyl, into the hydrocarbon residue diminishes or abolishes inhibitory capacity. The inhibition produced by the fatty acids is neither due to calcium binding nor due to prevention of effective antigen-antibody interaction; the fatty acids probably inhibit by acting on an antigen-antibody-activated step. The inhibition of the anaphylactic release of histamine and slow reacting substance produced by caproic or decanoic acid can be reversed by the enhancing effect of succinic acid, and vice versa. Thus, compounds normally present in mammalian tissue can greatly influence the intensity of the in vitro anaphylactic reaction in the guinea pig.
Anaphylaxis↗
The anaerobic decomposition of benzoic acid during methane fermentation. IV. Dearomatization of the ring and volatile fatty acids formed on ring rupture.
A possible pathway for the anaerobic utilization of benzoic acid by a methanogenic consortium is suggested. Cyclohexane carboxylic acid and 1-cyclohexene-1-carboxylic acid have been identified as intermediates before ring rupture. Suprisingly, 3-cyclohexene-1-carboxylic acid interferes with utilization of other cyclic acids. In addition, isobutyric acid or short chain acids containing carbon-carbon double bonds could not be used without induction periods of a week or longer. A number of volatile fatty acids (heptanoic, valeric, butyric, propanoic, and acetic) have been identified and are suggested intermediates.
Anaerobiosis↗
Polyhydroxyalkanoates form potentially a key aspect of aerobic phosphorus uptake in enhanced biological phosphorus removal.
Eighteen anaerobic/aerobic batch experiments were conducted with a variety of volatile fatty acids (VFAs) on a sequencing batch reactor (SBR) population displaying enhanced biological phosphorus removal (EBPR). A statistically significant (P << 0.01 for all variables) correlation between aerobic phosphorus uptake and polyhydroxyalkanoates (PHAs) quantity and form was observed. The results suggest that poly-3-hydroxy-butyrate (3HB) results in significantly higher aerobic phosphorus (P) uptake per unit mmoles as carbon (mmoles-C) than poly-3-hydroxy-valerate (3HV). The results showed that acetic and isovaleric acids resulted in higher P removals (relative to propionic and valeric acids) during EBPR batch experiments not because of higher PHAs quantity, but largely because the predominant type was 3HB rather than 3HV. In contrast propionic and valeric acids resulted in 3HV, and showed much lower aerobic P uptake per unit PHAs.
Bacteria, Aerobic↗
Methylmalonic/beta-hydroxy-n-valeric aciduria due to methylmalonyl-CoA mutase deficiency.
A patient with methylmalonic and beta-hydroxy-n-valeric aciduria, apparently due to deficiency of methylmalonyl-CoA mutase, is described. The excretion of beta-hydroxy-n-valerate did not parallel that of beta-hydroxypropionate and methylmalonate but was observed, together with beta-keto-n-valerate, only during ketosis. beta-Hydroxy-n-valerate excretion thus correlates primarily not with the pool size of propionyl-CoA but with that of acetyl-CoA, and may occur during ketosis in any disorder causing accumulation of propionyl-CoA.
Amino Acid Metabolism, Inborn Errors↗
Anion conductance of frog muscle membranes: one channel, two kinds of pH dependence.
Anion conductance and permeability sequences were obtained for frog skeletal muscle membranes from the changes in characteristic resistance and transmembrane potential after the replacement of one anion by another in the bathing solution. Permeability and conductance sequences are the same. The conductance sequence at pH = 7.4 is Cl(-) Br(-) > NO(3) (-) > I(-) > trichloroacetate >/= benzoate > valerate > butyrate > proprionate > formate > acetate >/= lactate > benzenesulfonate >/= isethionate > methylsulfonate > glutamate >/= cysteate. The anions are divided into two classes: (a) Chloride-like anions (Cl(-) through trichloroacetate) have membrane conductances that decrease as pH decreases. The last six members of the complete sequence are also chloride like. (b) Benzoate-like anions (benzoate through acetate) have conductances that increase as pH decreases. At pH = 6.7 zinc ions block Cl(-) and benzoate conductances with inhibitory dissociation constants of 0.12 and 0.16 mM, respectively. Chloride-like and benzoate-like anions probably use the same channels. The minimum size of the channel aperture is estimated as 5.5 x 6.5 A from the dimensions of the largest permeating anions. A simple model of the channel qualitatively explains chloride-like and benzoate-like conductance sequences and their dependence on pH.
Acetates↗
Isovalericacidemia appearing as diabetic ketoacidosis.
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Amino Acid Metabolism, Inborn Errors↗
Hormonal therapy of renal carcinoma alone and in association with cytostatic drugs.
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Adult↗