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1.
Summary. Previous investigations showed an impairment of amino acids (AA) metabolism in amyotrophic lateral sclerosis (ALS). It was
hypothesized that excitatory AA may play an important role in the etiopathogenesis of this disease. The aim of the study was
to determine plasma AA concentrations in ALS patients, and to examine the relationship between AA and the clinical state of
ALS patients, the type of ALS onset and the duration of the disease. The study involved 20 ALS patients and 30 control group
people. The AA analysis was performed by ion – exchange chromatography on an automatic AA analyser. The results showed significantly
decreased concentrations of valine, isoleucine, leucine, tyrosine and aspartate in the plasma of the whole group of ALS patients
compared to the control group, and a significantly decreased concentration of arginine in the patients with a long duration
of ALS compared to the patients with a short duration. The clinical state of ALS patients significantly influenced only plasma
alanine concentration. Other plasma AA concentrations were not significantly associated with clinical parameters of the disease.
Our study confirms that metabolic abnormalities concerning AA exist in ALS patients. However, the normal plasma glutamate
concentration observed in this study in the whole group of ALS patients compared to the controls does not exclude that this
excitatory AA may play a role in neurodegeneration in ALS.
Received June 22, 2002 Accepted October 3, 2002 Published online January 23, 2003
Correspondence: Joanna Iłżecka M.D., Department of Neurology, Medical University, Jaczewskiego 8, 20-954 Lublin, Poland,
Fax: +48 81 742 55 34, E-mail: Ilzecka@medscape.com 相似文献
2.
Summary. Secondary amino acid disturbances from circulatory responses during hypoxia may cause problems in interpreting plasma amino
acid profiles of sick babies investigated for possible inherited defects. Systematic studies to characterise them are difficult
in man. We investigated the effects of hypoxia on plasma amino acids by studying 9 late gestation fetal sheep in utero during 11 one hour episodes of moderately severe isocapnic hypoxia. In 6 experiments, maternal plasma amino acids were also
monitored. Fourteen fetal plasma amino acids increased significantly, with the largest proportionate changes in alanine, valine,
leucine, isoleucine, phenylalanine, tyrosine, ornithine and lysine. Maternal amino acids did not increase. Probable explanations
were reflex peripheral vasoconstriction in skeletal muscle beds and decreased hepatic blood flow. The findings extend our
knowledge of the fetal response to hypoxic stress, demonstrate the importance of skeletal muscle in branched-chain amino acid
metabolism, and should help with interpretation of postnatal plasma amino acid disturbances.
Received January 29, 1999, Accepted February 22, 1999 相似文献
3.
Summary. Since peptide quinones possess great clinical potential in targeted chemotherapy, several series of novel N-quinonyl amino
acids have been synthesized and their first products of reduction were studied by EPR spectroscopy. EPR spectra of the corresponding
radical adducts were identified by computer simulation. The dependence between the splitting constants and the chemical structure
of the N-quinonyl amino acids anion radicals was examined.
Received January 4, 2000; Accepted March 14, 2000 相似文献
4.
P. Tsiboli G. Konstantinidis Y. Skendros A. Katsani Dr. T. Choli-Papadopoulou 《Amino acids》1997,13(1):13-23
Summary Methylated lysines (N
-mono-methylated, N
-di-methylated and N
-tri-methylated) have been identified after derivatization with orthophthaldialdehyde (OPA) by using pre-column and post-column derivatization techniques.Also the N
-acetylated lysine and N
-formylated lysine have been identified by OPA post-column derivatization techniques but only in free form due to their instability under acidic conditions which are used for protein hydrolysis.Additionally, all the modified amino acids mentioned above have been derivatized with DABITC/PITC, an Edman reagent, and identified as DABTH-derivatives on thin-layer polyamide sheets. 相似文献
5.
Summary. The effect of dietary sulfur amino acids on the taurine content of rat blood and tissues was investigated. Three types of
diet were prepared for this study: a low-taurine diet (LTD), normal taurine diet (NTD; LTD + 0.5% Met), and high-taurine diet
(HTD; LTD + 0.5% Met + 3% taurine). These diets had no differing effect on the growth of the rats. The concentration of taurine
in the blood from the HTD- and NTD-fed rats was respectively 1,200% and 200% more than that from LTD-. In such rat tissues
as the liver, the taurine content was significantly affected by dietary sulfur amino acids, resulting in a higher content
with HTD and lower content with LTD. However, little or no effect on taurine content was apparent in the heart or eye. The
activity for taurine uptake by the small intestine was not affected by dietary sulfur amino acids. The expression level of
taurine transporter mRNA was altered only in the kidney under these dietary conditions: a higher expression level with LTD
and lower expression level with HTD.
Received January 8, 2002 Accepted January 18, 2002 Published online August 20, 2002
Authors' address: Dr. Hideo Satsu, Laboratory of Food Chemistry, Department of Applied Biological Chemistry, Graduate School of Agricultural
and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan, Fax: +81-3-5841-8026 E-mail: asatsu@mail.ecc.u-tokyo.ac.jp
Abbreviations: HTD, high-taurine diet; NTD, normal taurine diet; LTD, low-taurine diet; TAUT, taurine transporter; CSA, cysteine sulfinate;
CDO, cysteine dioxygenase; CSAD, cysteine sulfinate decarboxylase; PBS, phosphate-buffered saline; DIDS, 4,4′-diisothiocyanostilbene-2′,2′-disulfonic
acid 相似文献
6.
The effects of thiopentone on free intracellular amino acids in polymorphonuclear leucocytes 总被引:1,自引:0,他引:1
Summary. Previous studies have shown the inhibitory effects of thiopentone on polymorphonuclear leucocyte (PML) function. However,
major biochemical mechanisms which have been involved are still unknown. The aim of this study was therefore to investigate
thiopentone's effects on intracellular amino acid metabolism in PML using both advanced PML separation – and HPLC techniques,
especially developed for this purpose and precisely validated in our institute. Overall, our study indicates important dose-dependent
alterations of free intracellular amino acid metabolism following thiopentone treatment and draw attention to the biochemical
mechanisms which may be involved in both thiopentone-induced modulation in PML function and cellular immunocompetence.
Received April 4, 1999 相似文献
7.
U. Kazmaier 《Amino acids》1996,11(3-4):283-299
Summary Deprotonation ofN-protected amino acid allylic esters with LDA at –78°C and subsequent addition of a metal salt presumably results in the formation of a chelated metal enolate which undergoes Claisen rearrangement upon warming up to room temperature, giving rise to unsaturated amino acid. Many different metal salts can be used for chelation, but in general the best results are obtained with zinc chloride. Due to the fixed enolate geometry, as a result of chelate formation, and a strong preference for thechair like transition state, the rearrangement proceeds with a high degree of diastereoselectivity. This methodology can be applied to acyclic as well as to cyclic substrates, and even to peptides, and allows for the synthesis of amino acids containing quaternary carbon centers. 相似文献
8.
Summary (Z)--[(Benzyloxy)- or (tert.-butyloxy)carbonylamino]- (thienyl)-or (furyl)-acrylic acids and their esters were prepared by known methods and hydrogenated to the corresponding optically active alanine derivatives with optical yields in the range of 58–93% ee using the cationic rhodium complex of PROPRAPHOS. 相似文献
9.
Summary. Background: Dysphagia and eating difficulties are highly prevalent in long term care patients. Evaluation of their nutritional status
is complicated by comorbidity, frailty and individual patterns of feeding. In previous studies we found vitamin deficiencies
(folic acid B6 and B12) in orally fed elderly in early stages of oropharyngeal dysphagia despite satisfactory nutritional
parameters (BMI, albumin and hemoglobin). The aim of this study is to evaluate the plasma amino acids levels in these hand-oral
fed elderly patients with dysphagia.
Methods: Plasma amino acids were measured in 15 orally fed elderly patients in early functional outcome swallowing scale (FOSS),
stage 2, and compared with those of 15 matched nasogastric-tube-fed counterparts.
Results: The plasma levels of all measured amino acids, ratio of essential to nonessential, levels of conditionally essential and
the immune-enhancing amino acids were similar in both groups and within the normal range of our laboratory. The traditional
nutritional parameters were also similar in both groups and within the normal range.
Conclusions: Plasma levels of amino acids in elderly patients in early stage of FOSS are satisfactory, supporting the view that their
protein intake is adequate. Further studies should concentrate on patients in advanced stages of FOSS. 相似文献
10.
Summary. Sulfate and taurine are major end products of sulfur-containing amino acid metabolism in mammals including humans, and they
are excreted in urine. Average excretions (μmol/mg of creatinine) in the morning urine of 58 female college students were: total (free plus ester) sulfate (a), 12.53
± 3.85; free sulfate, 11.57 ± 3.69; taurine, 0.78 ± 0.53. Ratio of total sulfate and taurine was 10 : 0.6. Regression lines
obtained by plotting total sulfate, free sulfate, or total sulfate plus taurine against urea have shown that the former excretions
are significantly correlated with urea excretion. Excretion of total sulfate at zero point of urea excretion (b) was 5.30,
which corresponded to 42.3% of average excretion (12.53) and was assumed to be derived from dietary sulfate. The difference
7.23 (a − b) seemed to be derived from sulfur-containing amino acids. It was pointed out that the difference of average sulfate
excretion and sulfate excretion at zero urea excretion, namely a − b, was appropriate for the metabolic index of sulfur-containing
amino acids of the group examined. As free sulfate constituted 92.3% of total sulfate, excretion of ester sulfate was at a
constant level, and that of taurine was not significantly correlated with urea excretion, the value of free sulfate corresponding
to the value a − b of total sulfate mentioned above seemed to be a reliable and convenient index in the assessment of sulfur-containing
amino acid metabolism.
Received December 3, 2001 Accepted January 2, 2002 Published online August 30, 2002
Authors' address: Dr. Toshihiko Ubuka, Department of Clinical Nutrition, Kawasaki University of Medical Welfare, Kurashiki Okayama, 701-0193
Japan, E-mail: ubukatos@mw.kawasaki-m.ac.jp 相似文献
11.
Bittner S 《Amino acids》2006,30(3):205-224
Summary. Quinones and amino acids are usually compartmentally separated in living systems, however there are several junctions in which
they meet, react and influence. It occurs mainly in wounded, cut or crushed plant material during harvest, ensiling or disintegrating
cells. Diffusing polyphenols are oxidized by polyphenol oxidases (PPOs) to quinonic compounds, which associate reversibly
or irreversibly with amino acids and proteins. The reaction takes place with the free nucleophilic functional groups such
as sulfhydryl, amine, amide, indole and imidazole substituents. It results in imine formation, in 1,4-Michael addition via
nitrogen or sulphur and in Strecker degradation forming aldehydes. The formation and activity of quinone–amino acids conjugates
influences the colour, taste, and aroma of foods. Physical and physiological phenomena such as browning of foods, discoloration
of plants during processing, alteration of solubility and digestibility, formation of humic substances, germicidal activity,
cytotoxicity and more occur when quinones from disintegrating cells meet amino acids. The mechanisms of toxicity and the pathways
by which PCBs may be activated and act as a cancer initiator include oxidation to the corresponding quinones and reaction
with amino acids or peptides. Sclerotization of insect cuticle is a biochemical process involving also the reaction between
quinones and amino acid derivatives. 相似文献
12.
13.
Kurić L 《Amino acids》2007,33(4):653-661
Summary. The subject of this paper is a digital approach to the investigation of the biochemical basis of genetic processes. The digital
mechanism of nucleic acid and protein bio-syntheses, the evolution of biomacromolecules and, especially, the biochemical evolution
of genetic language have been analyzed by the application of cybernetic methods, information theory and system theory, respectively.
This paper reports the discovery of new methods for developing the new technologies in genetics. It is about the most advanced
digital technology which is based on program, cybernetics and informational systems and laws. The results in the practical
application of the new technology could be useful in bioinformatics, genetics, biochemistry, medicine and other natural sciences. 相似文献
14.
Bio-available amino acids and mineral nitrogen forms in soil of moderately mown and abandoned mountain meadows 总被引:1,自引:0,他引:1
Summary. The abandonment of traditional mowing methods of mountain meadows in the Czech Republic at the end of the last century has
resulted in secondary re-colonization of these areas. Altered accumulation of plant biomass resulted in a deceleration of
N turnover. A mountain meadow may be regarded as a N-limited ecosystem in which plant nutrition is dependent on direct uptake
of soil amino acids. The composition and distribution of ammonium ions, nitrate ions and the 16 bio-available proteinaceuous
amino acids were investigated in the top 7 cm of the Ah horizon of a Gleyic Luvisol in a long-term moderately mown meadow
and an eleven year old, abandoned or uncut meadow. Ammonium N has a dominant role in both ecosystems. The moderately mown
meadow showed accelerated N-turnover and higher net ammonization. The plant community showed a dependence on this form. Plant
utilization of nitrates and amino acids appeared to be negligible. The uncut or abandoned meadow showed net ammonization from
May (start of the experiment) through August, after which plant N-uptake consisted only of amino acids due to microbial immobilization.
The release of bio-available nitrogen from spring until the beginning of summer in the Ah horizon was too low to explain total
plant N-uptake. Glutamic acid, arginine and aspartic acids had the highest concentrations of any of the amino acids analyzed.
Authors’ address: Pavel Formánek, Department of Geology and Pedology, Mendel University of Agriculture and Forestry, Zemedelska
3, 613 00 Brno, Czech Republic 相似文献
15.
The standard Gibbs energies of transfer of anions and cations of amino acids and small peptides across the water nitrobenzene interface were determined with the help of a novel electrochemical technique using three-phase electrodes. This is the first time that reliable data are reported for the anions of amino acids. The main result is that the standard Gibbs energies of transfer of the anion and cation of an amino acid are almost the same. 相似文献
16.
Suresh Babu Vommina V. Gopi Hosahudya N. 《International journal of peptide research and therapeutics》1999,6(2-3):173-178
Summary The pentafluorophenyl esters of Boc-/Z-amino acids are used for the preparation of the key intermediates α-aminoacyldiazomethanes
during the homologation of α-amino acid to β-amino acid. Thus, all the Boc-/Z-amino acid diazoketones and the corresponding
β-amino acids were obtained as crystalline solids in satisfactory yields. 相似文献
17.
Summary The lipophilicity (or hydrophobicity) of amino acids is an important property relevant for protein folding and therefore of great interest in protein engineering. For peptides or peptidomimetics of potential therapeutic interest, lipophilicity is related to absorption and distribution, and thus indirectly relates to their bioactivity. A rationalization of peptide lipophilicity requires basic knowledge of the lipophilicity of the constituting amino acids. In the present contribution we will review methods to measure or calculate the lipophilicities of amino acids, including unusual amino acids, and we will make a comparison between various lipophilicity scales. 相似文献
18.
Free and bound amino acids and proteins in developing grains of rice with enhanced lysine/proteins 总被引:2,自引:0,他引:2
G. W. Schaeffer F. T. Sharpe 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(6-7):878-881
Free amino acids were determined in developing seed of a rice mutant with enhanced grain lysine. This phenotype frequently
has enhanced protein. Some free amino acids of developing seed are inversely related to the level of total amino acids in
proteins of the mature grain. Amino acids that were enhanced in protein, including aspartic acid, threonine, methionine and
lysine, were notably lower in the free amino-acid pool. Our conclusion is that mutant-developing grains process aspartate
amino acids more rapidly than the controls. Conversely, arginine, valine and glutamic acid/glutamine accumulate as free amino
acids with mutant/control ratios of 1.39, 1.29 and 1.12, respectively. Glutamic acid/glutamine in proteins of mature seeds
is lower in the mutant than the control. 3H-lysine incorporation showed enhanced isotope incorporation into at least four proteins. One mutant protein was less actively
labelled than analogous controls. The 3Hlysine pattern indicates processing modifications in this useful rice mutant.
Received: 14 October 1996/Accepted: 8 November 1996 相似文献
19.
Aleksandra Olma Dirk Tourwé 《International journal of peptide research and therapeutics》2000,7(2):93-96
Summary Novel endomorphin-2 analogs containing the unusual amphiphilic amino acid (R)- and (S)-α-hydroxymethyltyrosine in position 1 and (R)- and (S)-α-hydroxymethylphenylalanine in the positions 3 and 4 were synthesized via the solid-phase method. The binding characteristics
of the synthetic analogs may suggest that α-hydroxymethyl substitution of amino acid residues influences the conformation
of a peptide much more than simply increasing the local amphiphilic character of the peptide. 相似文献
20.
In queen honey bees the free amino acid content in the haemolymph clearly depends on the physiological function and social environment of the individual. While in drones and workers the content of free amino acids increases after emergence until it reaches a peak in 5-day-old animals and decreases afterwards, the amino acid content in queens reaches its highest level (>60 nmol/ microl haemolymph) with the onset of egg laying (10 d of age). This level is about 2.5 times more than the highest level found in workers. Queens maintain this high level also when they are older (>30 d) and continue to lay eggs in average colonies. As in drones and workers, in queens the predominant amino acid is proline, which accounts for more than 50% of the total content of free amino acids in egg-laying individuals. When 10-day-old queens are prevented from mating and do not lay eggs, their amino acid content is significantly lower compared to laying queens of the same age. Also the social environment influences the contents of free amino acids in queens. When virgin queens were kept for 6 days with 20 worker bees and sufficient honey and pollen in an incubator, they had significantly lower concentrations of amino acids than virgin queens living for the same period with about 8000 workers in a colony. Most probably, the high amino acid concentration in the haemolymph is the basis for the high protein synthesis activity of laying queens. 相似文献