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PubMed1978

Isolation of 3beta,7alpha-dihydroxychol-5-enoic acid, an intermediate of chenodeoxycholic acid biogenesis, and 3alpha,7alpha-dihydroxychol-4-enoic acid from bladder bile of hens.

Two Lifschütz-positive C24-bile acids were isolated from bladder bile of hens. One of these was identified by isotope dilution experiments after conversion to a 3H-labeled compound, and also by GLC after methoxylation, as 3beta,7alpha-dihydroxychol-5-enoic acid, a key intermediate of chenodeoxycholic acid biogenesis. The other, to which the structure 3beta,7alpha-dihydroxychol-4-enoic acid had been assigned previously, was proved to be its 3alpha-epimer by several experiments. These findings favor the alternative pathway of chenodeoxycholic acid biogenesis proposed by Yamasaki and his associates.

Animals↗

PubMed2000

X-ray studies on crystalline complexes involving amino acids and peptides. XXXV. Invariance and variability in amino acid aggregation in the complexes of maleic acid with L-histidine and L-lysine.

The crystal structures of complexes of maleic acid with L-histidine and L-lysine have been determined. The two crystallographically independent amino acid molecules in the L-histidine complex have different closed conformations, while the lysine molecule in its complex has the most favourable conformation sterically with an all-trans sidechain trans to the alpha-carboxylate group. The maleic acid molecules exist as semi-maleate ions of similar conformation and contain a symmetric O...H...O hydrogen bond. Amino acid cations and semi-maleate anions aggregate into alternate layers in both the structures. The arrangement of molecules in the histidine layer in L-histidine semi-maleate is closer to that in the crystals of the free amino acid than in other L-histidine complexes. On the other hand, the arrangement of lysine molecules in its semi-maleate complex is different from any observed so far. However, the well established characteristic interaction patterns involving amino and carboxylate groups still play a major role in holding the molecules together in the crystal of the complex.

Amino Acids↗

PubMed1984

Structure of ascorbic acid and its biological function. Determination of the conformation of ascorbic acid and isoascorbic acid by infrared and ultraviolet investigations.

The four O-H bands of ascorbic acid could be assigned by means of infrared investigations. It could be shown by electron spin resonance and nuclear magnetic resonance measurements that the radical sodium ascorbate is formed by a cyclic side-chain structure resulting in a loss of C(6)-OH and C(3)-OH. The C(2) = C(3) double bond is still maintained as could be shown by infrared and ultraviolet absorption spectroscopy. In the case of complete oxidation of ascorbic acid to dehydroascorbic acid, C(6)-OH is reestablished (indicating the reopening of the furanoid ring), while C(2)-OH as well as the C(2) = C(3) double bond have disappeared due to the deprotonation of C(2)-OH and C(3)-OH. In the case of isoascorbic acid and its radical potassium isoascorbate similar results are obtained with one distinct difference: in the case of isoascorbic acid, C(2)-OH does not appear while C(3)-OH exhibits a shoulder.

Ascorbic Acid↗

PubMed1973

Relationships among deoxyribonucleic acid, ribonucleic acid, and specific transfer ribonucleic acids in Escherichia coli 15T - at various growth rates.

The levels of macromolecules in Escherichia coli 15T(-) growing in broth, glucose, succinate, and acetate media were determined to compare relationships among deoxyribonucleic acid (DNA), ribosomal ribonucleic acid (rRNA), transfer RNA (tRNA), and protein in cells at different growth rates. DNA and protein increased in relative amounts with decreasing growth rate; relative amounts of rRNA and tRNA decreased, tRNA making up a slightly larger proportion of RNA. For several amino acid-specific tRNAs studied, acceptor capacities per unit of DNA increased with increasing growth rate. The syntheses of tRNA and rRNA are regulated by similar, yet different, mechanisms. Chromatographic examination on columns of benzoylated diethylaminoethyl-cellulose of isoaccepting tRNAs for arginine, leucine, lysine, methionine, phenylalanine, serine, and valine did not reveal differences in the isoaccepting profiles for rapidly (broth culture) and slowly growing (acetate culture) cells. Therefore, isoacceptors for individual amino acids appear to be regulated as a group. Lower efficiencies of ribosomal function in protein synthesis can be explained, in part, by a low ratio of tRNA to the number of ribosomes available and by a decreasing concentration of tRNA with decreasing growth rate. Data on the tRNAs specific for seven amino acids indicate that the decreasing concentration of tRNA is a general event rather than a severe limitation of any one tRNA or isoaccepting tRNA.

Acetates↗

PubMed1967

Effect of ethylenediaminetetraacetic acid-Tris(hydroxymethyl)aminomethane on release of the acid-soluble nucleotide pool and on breakdown of ribosomal ribonucleic acid in Escherichia coli.

Brief treatment of Escherichia coli with 2 x 10(-4)m ethylenediaminetetraacetic acid (EDTA)-0.12 m tris(hydroxymethyl)aminomethane (Tris), pH 8.0, or 0.12 m Tris alone resulted in the release of the acid-soluble nucleotide pool at 3 or 23 C. Exposure to EDTA-Tris for up to 90 min at 3 C did not result in the release of increasing amounts of 260-mmu-absorbing material. At 23 and 37 C, EDTA-Tris resulted in a steady increase in acid-soluble 260-mmu-absorbing material. Previous growth environment did not alter the release. There appeared to be degradation of 23S ribonucleic acid (RNA) after 10 min of exposure at 23 C. In addition, there was degradation of nucleotides to nucleosides and bases. This occured either within the cells with altered permeability or in the periplasmic space. This occurred in the presence of EDTA and Tris but was not seen with EDTA-phosphate. The mechanism of this degradation is unclear, since it occurs in ribonuclease I-deficient strains. Exposure to Tris buffer for long periods of time at 23 C resulted in release of the nucleotide pool and in degradation of RNA and nucleotides. These studies point out that the EDTA-Tris effect on E. coli must be divided into two parts, an early (4 to 5 min) change in permeability and a later phase of actual RNA breakdown and nucleotide degradation. Studies utilizing EDTA and Tris as agents altering permeability must thus be viewed with caution. Although the cells are viable, they have lost their acid-soluble nucleotide pool and have undergone degradation of some ribosomal RNA.

Buffers↗

PubMed1982

Limiting amino acids in bengal gram (Cicer arietinum) as determined from blood amino acid levels and amino acid supplementation studies in the rat.

The limiting amino acids of Bengal gram (Cicer arietinum) were determined from plasma amino acid score and ratio and growth response of weanling rats to supplements of amino acids. The results indicated that methionine, threonine and tryptophan are the most limiting amino acids. Protein efficiency ratio of raw and cooked Bengal gram fed at a dietary level of 10% protein increased from 2.7 to 3.7 and 2.4 to 3.4, respectively, on supplementing the diets with methionine, threonine and tryptophan. Plasma levels of lysine, methionine, threonine and tryptophan were similar in rats fed raw or cooked Bengal gram, indicating that the trypsin or other inhibitors that may be present in the raw gram do not affect the biological availability of these amino acids.

Amino Acids↗

PubMed2005

Quantitative acylcarnitine profiling in peripheral blood mononuclear cells using in vitro loading with palmitic and 2-oxoadipic acids: biochemical confirmation of fatty acid oxidation and organic acid disorders.

Organic acid (OAD) and fatty acid oxidation disorders (FAOD) are inborn errors of metabolism often presenting with life-threatening metabolic decompensation followed by (irreversible) organ failure, and even death during catabolic state. Most of these diseases are considered as treatable, and metabolic decompensations can be avoided by early diagnosis and start of therapy. Confirmation of suspected diagnosis currently relies on enzymatic and mutation analyses and in vitro loading of palmitic acid in human skin fibroblast cultures. Furthermore, in some cases potentially life-threatening in vivo loading or fasting tests are still performed. In this study, we established a standardized in vitro loading test in peripheral blood mononuclear cells (PBMC) that allows reliable biochemical confirmation of a suspected diagnosis within 1 week. Patients with confirmed diagnosis of short-, medium-, very-long-chain, and long-chain 3-hydroxyacyl-CoA dehydrogenase deficiencies, methylmalonic, propionic, isovaleric acidurias, and glutaric aciduria type I were included in the study. PBMC, isolated from heparinized venous blood samples of these individuals were incubated for 5 days with palmitic acid or 2-oxoadipic acid (glutaric aciduria type I), respectively, and quantitative acylcarnitine profiling was subsequently performed in supernatants using electrospray ionization tandem mass spectrometry. All patients were clearly identified, including those with mild biochemical phenotypes who, in particular, are at risk to be missed under balanced metabolic conditions. In glutaric aciduria type I, the same results were also obtained using lymphoblasts. In conclusion, our assay allows biochemical confirmation of a number of FAOD and OAD and could easily be implemented into the confirmatory diagnostic work-up.

Adipates↗

PubMed1996

N-terminal sequence of amino acids and some properties of an acid-stable alpha-amylase from citric acid-koji (Aspergillus usamii var.).

An acid-stable alpha-amylase (AA) was purified from an acidic extract of citric acid-koji (A. usamii var.). The N-terminal sequence of the first 20 amino acids of the enzyme was identical with that of AA from A. niger, but the two enzymes differed in molecular weight. HPLC analysis for identifying the anomers of products indicated that the AA hydrolyzed maltopentaose (G5) at the third glycoside bond predominantly, which differed from Taka-amylase A and the neutral alpha-amylase (NA) from the citric acid-koji.

Amino Acid Sequence↗

PubMed2004

A PCR assay for detection of acetic acid-tolerant lactic acid bacteria in acidic food products.

A PCR assay for the detection of acetic acid-tolerant lactic acid bacteria in the genera of Lactobacillus and Pediococcus was developed in this study. Primers targeting the bacterial 16S rRNA gene were newly designed and used in this PCR assay. To determine the specificity of the assay, 56 different bacterial strains (of 33 genera), 2 fungi, 3 animals, and 4 plants were tested. Results were positive for most tested bacterial members of 16S rRNA gene-based phylogenetic groups (classified in the Lactobacillus casei and Pediococcus group), including Lactobacillus fructivorans, Lactobacillus brevis, Lactobacillus buchneri, Lactobacillus plantarum, and Lactobacillus paracasei. For all other bacterial strains and eukaryote tested, results were negative. Bacterial DNA for PCR was prepared with a simple procedure with the use of Chelex 100 resin from culture after growth in deMan Rogosa Sharpe broth (pH 6.0). To test this PCR assay for the monitoring of the acetic acid-tolerant lactic acid bacteria, L. fructivorans was inoculated into several acidic food as an indicator. Before the PCR, the inoculation of 10 to 50 CFU of bacteria per g of food was followed by a 28-h enrichment culture step, and the PCR assay allowed the detection of bacterial cells. Including the enrichment culture step, the entire PCR detection process can be completed within 30 h.

Acetic Acid↗

PubMed1992

Renal organic acid transport: uptake by rat kidney slices of a furan dicarboxylic acid which inhibits plasma protein binding of acidic ligands in uremia.

The furan dicarboxylic acid, 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (5-propyl FPA), accumulates in uremic plasma and inhibits the binding of various drugs and marker ligands that are organic acids. 5-Propyl FPA is excreted unchanged in human urine and active tubular secretion is likely to be involved because of its high affinity for albumin. The uptake of 5-propyl FPA by rat kidney slices has been measured and compared with that of p-aminohippurate (PAH). The mean (+/- S.D.) slice/medium ratio for uptake of 5-propyl FPA (76 microM) was 22.7 +/- 2.6 (n = 11) and for PAH (75 microM) was 15.9 +/- 3.2 (n = 9) after incubation for 90 min at 25 degrees C. 5-Propyl FPA (149-829 microM) inhibited the uptake of PAH (77 microM) in a concentration-dependent manner, and likewise, PAH (150-830 microM) inhibited the uptake of 5-propyl FPA (77 microM). The mean apparent Km and Vmax values for the uptake of 5-propyl FPA were 194 +/- 125 microM and 55 +/- 28 nmol/g kidney/min, respectively, and 487 +/- 179 and 99 +/- 46 nmol/g kidney/min, respectively, for PAH. The kinetics of inhibition of uptake of PAH by 5-propyl FPA were mainly competitive. 5-Propyl FPA is thus likely to undergo active tubular secretion in a similar way to PAH, and this furan dicarboxylic acid, therefore, has the potential to inhibit the renal excretion of various drugs, drug conjugates and other endogenous organic acids.

Animals↗

PubMed2003

The effects of ursodeoxycholic acid alone and ursodeoxycholic acid plus low-dose acetylsalicylic acid on radiolucent gallstones.

BACKGROUND/AIMS: Mucin, a high molecular weight glycoprotein secreted by the gallbladder and biliary duct epithelium, is a pronucleating agent in experimental and human gallstone disease. Blockage of mucin release with aspirin inhibits the formation of primary gallstones in animal models. The aim of this study was to compare the effects of ursodeoxycholic acid alone and plus low-dose aspirin on dissolution of solitary or multiple gallstones. METHODS: There were three treatment groups comprising 43 patients with cholesterol gallstones: Group I (n=16, 13 females, three males) was given ursodeoxycholic acid (15 mg. kg. day) alone and Group II (n=14, 12 females, two males) was treated with aspirin (100 mg/day) in addition to ursodeoxycholic acid cholic. Group III was a control group of 13 cases (11 females, two males) who were monitored without medical treatment. Stone dissolution rates were evaluated sonographically in all patients at three month intervals during the treatment period. RESULTS: After 12 months of treatment, stone dissolution was found in six (37.5%) of the patients in Group I and six (42.8%) of the patients in Group II. The difference in both treatment groups was significant compared to controls (p<0.05) but there was no significant difference between the two treatment groups (p>0.05). Of the cases in whom dissolution was achieved, all patients had multiple gallstones except for one with a solitary stone in Group I. Gallstones were not dissolved of any subject of group III. CONCLUSIONS: The results showed that ursodeoxycholic acid cholic therapy is more effective in the dissolution of multiple gallstones than of solitary ones. Combination with aspirin did not potentiate the efficacy of ursodeoxycholic acid cholic.

Adult↗

PubMed1994

Effects of side chain length on ionization behavior and transbilayer transport of unconjugated dihydroxy bile acids: a comparison of nor-chenodeoxycholic acid and chenodeoxycholic acid.

13C-NMR spectroscopy was used to examine the effect of side chain length on the ionization properties and transmembrane transport rate of 3 alpha,7 alpha-dihydroxy bile acids. When solubilized in taurocholate micelles, [23-13C]nor-chenodeoxycholic acid (nor-CDCA) had a pKa of 6.1, similar to that of CDCA (pKa 6.2), its C24 homologue. In unilamellar phosphatidylcholine vesicles, the pKa of nor-CDCA was 7.0, whereas that of CDCA was 6.6. Lineshape analysis indicated that the rate of ionization of nor-CDCA as a micellar solute or as a vesicle component was very slow (0.4 x 10(5) sec-1) compared to that of acetic acid in water (8.7 x 10(5) sec-1). Lineshape analysis of spectra of the protonated form of nor-CDCA at acidic bulk pH indicated that the transbilayer transport rate of nor-CDCA (580 sec-1) was six times faster than that of CDCA (100 sec-1). It is proposed that the shorter side chain of the nor-CDCA molecule causes it to reside more deeply inside the vesicle bilayer than CDCA, explaining its weaker ionization and more rapid flip-flop rate. These in vitro experiments imply that, in vivo, a given C23 nor-dihydroxy bile acid will ionize less readily when present in membranes, and it will also flip-flop faster than its C24 homologue.

Biological Transport↗

PubMed1987

Simultaneous liquid chromatographic determination of vanillylmandelic acid, homovanillic acid, and 5-hydroxy-3-indoleacetic acid in urine, using isocratic elution and electrochemical detection.

A method for the simultaneous measurement of vanillylmandelic acid, homovanillic acid and 5-hydroxyindoleacetic acid in urine is described. Based on reversed-phase liquid chromatography with electrochemical detection, the procedure employs isocratic elution, thus making it suitable for use in the less well-equipped clinical or research laboratory. A simple extraction of the acids from acidified urine into ethyl acetate, is followed by evaporating to dryness a portion of the organic layer, and redissolving the residue in chromatographic mobile phase. Up to 20 samples can be analysed in a single working day. The method is validated and the results obtained are compared with reference methods. The cause of contamination of the glassy carbon surface of the working electrode is investigated, and a simple electrochemical pretreatment is described that overcomes this problem. Finally, the extra clinical information that can be derived from multi-metabolite assays is considered.

Biogenic Amines↗

PubMed1988

Analysis of fatty acids by negative ion gas chromatography/tandem mass spectrometry: structural correlations between alpha-mycolic acid chains and delta-5-monounsaturated fatty acids from Mycobacterium phlei.

The analysis of a complex mixture of monounsaturated fatty acids from mycobacterium phlei is achieved by capillary gas chromatographic separation of their pentafluorobenzyl esters, formation of gas-phase carboxylate anions by electron capture ionization and decomposition of these anions by collision activation. This method allows the structural determination of fatty acid isomers by examination of their collisionally activated dissociation mass-analysed ion kinetic energy spectra. A good correlation is observed between the structure of the unsaturated fatty acids ranging from C24 to C27 and the methyl terminal part of the main chain of diunsaturated mycolic acids.

Fatty Acids↗

PubMed1994

Isolation and characterization of the reaction product of 4-diazobenzenesulfonic acid and gamma-carboxyglutamic acid: modification of the assay for measurement of beta-carboxyaspartic acid.

gamma-Carboxyglutamic acid (Gla)-containing proteins are extracellular proteins with enhanced cation or mineral-binding properties. Discovery of new Gla-containing proteins is facilitated by methods that decrease the number of steps and time involved in assaying for Gla. Reaction of 4-diazobenzenesulfonic acid (DBS) and Gla or Gla-containing proteins produces an intensely red-colored product. This method has been used to identify Gla-containing proteins in crude extracts of proteins. The reaction product of Gla and DBS has been purified by reversed-phase HPLC and characterized by uv-visible spectroscopy and electrospray ionization (ESI) mass spectrometry (MS). The red-colored product exhibits an absorption maximum at 530 nm. The ESI-MS data of the colored derivative of Gla are consistent with replacement of the two gamma-carboxyl groups in Gla with two DBS groups. DBS also reacts with another malonic acid derivative, beta-carboxyaspartic acid (Asa). The optimum conditions for colorimetric assay of Asa were established, and the potential of this reaction as an assay for Asa and Asa-containing proteins was studied.

1-Carboxyglutamic Acid↗

PubMedDate not supplied

A comparison of heart and liver fatty acid-binding proteins: interactions with fatty acids and possible functional differences studied with fluorescent fatty acid analogues.

Fatty acid-binding proteins (FABP) are distinct but related gene products which are found in many mammalian cell types. They are generally present in high abundance, and are found in those tissues where free fatty acid (ffa) flux is high. The function(s) of FABP is unknown. Also not known is whether all FABP function similarly in their respective cell types, or whether different FABP have unique functions. The purpose of these studies was to assess whether different members of the FABP family exhibit different structural and functional properties. Two fluorescent analogues of ffa were used to compare the liver (L-FABP) and heart (H-FABP) binding proteins. The propionic acid derivative of diphenylhexatriene (PADPH) was used to examine the physical properties of the ffa binding site on L- and H-FABP, as well as the relative distribution of ffa between FABP and membranes. An anthroyloxy-derivative of palmitic acid, 2AP, was used to monitor the transfer kinetics of ffa from liver or heart FABP to acceptor membranes, using a resonance energy transfer assay. The results demonstrate that the ffa binding sites of both FABP are hydrophobic in nature, although the L-FABP site is more nonpolar than the H-FABP site. Equilibration of PADPH between L-FABP and phosphatidylcholine (PC) bilayers resulted in a molar partition preference of greater than 20: 1, L-FABP PC. Similar studies with H-FABP resulted in a PADPH partition preference of only 3:1, H-FABP: PC. Finally, the transfer of 2AP from H-FABP to acceptor membranes was found to be 50-fold faster than transfer from L-FABP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2000

Synthesis of 9,12-dioxo-10(Z)-dodecenoic acid, a new fatty acid metabolite derived from 9-hydroperoxy-10,12-octadecadienoic acid in lentil seed (Lens culinaris Medik.)

The previously unknown linoleic acid peroxidation product 9,12-dioxo-10(Z)-decenoic acid (Z5) was detected in lentil seed flour (Lens culinaris Medik.) by electron impact mass spectrometry (EI-MS) after derivatization with pentafluorobenzyl-hydroxylamine-hydrochloride, methylation of acidic groups with diazomethane, and protection of hydroxylic groups with N-methyl-N-trimethylsilyl-trifluoroacetamide. The structure of the natural product was confirmed by synthesis of Z5, 9,12-dioxo-l0(E)-decenoic acid, and derivatives. EI-MS, nuclear magnetic resonance and gas chromatographic data of these compounds and synthetic intermediates are discussed.

Chromatography, Gas↗

PubMed1989

Efficacy and safety of a combination of chenodeoxycholic acid and ursodeoxycholic acid for gallstone dissolution: a comparison with ursodeoxycholic acid alone.

Chenodeoxycholic acid (CDC) and ursodeoxycholic acid (UDC) have distinct physicochemical and metabolic properties which, being complementary, should favor more rapid removal of cholesterol from gallstones when both bile acids are administered together. To see if the combination is more effective and well tolerated, we have compared 5 mg/kg of CDC plus 5 mg/kg of UDC with a 10-mg/kg dose of UDC alone in 120 patients with radiolucent, sonographically confirmed gallstones and characteristics favoring complete dissolution. Ursodeoxycholic acid was chosen as the reference because it dissolves stones faster and is better tolerated than CDC. To minimize the influence of stone size, the major determinant of dissolution, patients were divided, on admission, into two groups according to the maximum stone diameter: 50 had stones less than or equal to 5 mm, 70 had stones greater than 5 mm but less than 15 mm. The effects of treatment on stone dissolution evaluated by cholecystography and ultrasonography at 6, 12, and 24 mo, were analyzed by the actuarial life-table method. In the group with smaller stones, significantly more patients had obtained complete dissolution after treatment with the combination (52%) than after treatment with UDC alone (24%) at 6 mo. After longer periods, results were still better with the combination, although the differences from UDC alone became smaller. In the patients with larger stones, rates of complete and partial dissolutions were higher after treatment with the combination (51% vs. 24% with UDC) at 6 mo and again the differences had become smaller after longer treatment. Although not statistically significant, stone calcification occurred more often with UDC (7 cases) than with the combination (1 case). We conclude that CDC plus UDC is preferable to UDC alone because it dissolves stones more quickly, with a lower incidence of stone calcification, and may result in reduced cost of treatment.

Bile↗