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PubMed1983

Amino acid composition and zinc content of milk-clotting protease from Bacillus mesentericus strain 76.

The milk-clotting protease from Bacillus mesentericus strain 76 is free of carbohydrate and lacks cysteine and cystine. The amino acid composition indicates a single peptide chain with 304 residues. Five amino acids--aspartic acid, threonine, serine, glycine and alanine--represent one-half of the total residues. The enzyme contains 35 aromatic amino acids and 103 ionic amino acids. The observed constant value of the ratio Menzyme:Azinc is 1:1 for active and acid denatured enzyme preparations, indicating that 0.1 M acetic acid causes denaturation of the enzyme but it can not eliminate the zinc ions.

Amino Acids↗
PubMed1991

Studies on the proteolytic degradation of the beta-protein precursor by proteases purified from Alzheimer's disease brain.

In Alzheimer's disease, Down's syndrome, hereditary cerebral hemorrhage with amyloidosis of Dutch origin, and normal aging, amyloid accumulates in the brain parenchyma and blood vessels. The major protein in the deposits is the beta-protein, a 4-kD peptide possibly generated by an abnormal degradation of its precursor, the beta-protein precursor (beta PP). We found, as a second component of the brain amyloid, the serine protease inhibitor alpha 1-antichymotrypsin (ACT). Inasmuch as ACT is tightly associated with the beta-protein and is never found in other amyloidoses, we hypothesized a role for ACT in the degradation of the beta PP. We used synthetic peptides made according to the sequence flanking the N-terminus of the beta-protein to screen brain fractions for protease activity. After several purification steps, two protease fractions were found that can cleave the peptide between methionine and aspartic acid, aspartic acid being the N-terminus of the beta-protein. One protease is activated by calcium and inhibited by ACT, beta PP containing the Kunitz-type inhibitory domain, diisofluorophosphate, and 1,10-phenanthroline. This protease fraction is also able to degrade the beta PP in vitro. The second protease is a metal-dependent cysteine protease.

Alzheimer Disease↗
PubMed1966

Amino acid compostion of walls from single and filamentous cells of Clostridium acidiurici.

Gaffar, Abdul (Brigham Young University, Provo, Utah), David R. Terry, and Richard D. Sagers. Amino acid composition of walls from single and filamentous cells of Clostridium acidiurici. J. Bacteriol. 91:1618-1624. 1966.-The walls from single and filamentous cells of Clostridium acidiurici were shown to contain 11 amino acids: aspartic acid, serine, glutamic acid, proline, d-alanine, glycine, valine, methionine, valine, leucine, phenylalanine, and lysine. In the walls from cells grown at 37 C, d-alanine was the amino acid present in largest quantity, but in the walls from cells grown at 44 C there was a 50% reduction in the d-alanine content while the levels of the other amino acids were unchanged. Filamentous cells grown at 44 C, then brought to 37 C and transferred to fresh medium, fragmented into short cells within 30 min. Alanine racemase activity was the same in extracts from cells grown at both 37 and 44 C, suggesting that this enzyme was not the major controlling factor in the low content of d-alanine in filaments grown at 44 C. Spent medium from cultures grown at 44 C contained a significant amount of d-alanine, whereas there was no evidence of this amino acid in the spent medium from cultures grown at 37 C.

Alanine↗
PubMed1987

Determination of delta-aminobutyric acid and other amino acids in cerebrospinal fluid of pediatric patients by reversed-phase liquid chromatography.

The reversed-phase liquid-chromatographic system described here is capable of resolving the neurotransmitter amino acids aspartic acid, glutamic acid, and gamma-aminobutyric acid (GABA) plus 21 other amino acids in cerebrospinal fluid (CSF) in a single analysis. The amino acids, derivatized with o-phthalaldehyde, are separated in 65 min. Concentrations of glutamine less than or equal to 600 mumol/L can be measured at the same time as GABA greater than or equal to 10 nmol/L. Using this method, we have determined reference intervals for amino acids, including GABA, in CSF in a group of pediatric patients who underwent lumbar puncture before myelography, and who were subsequently shown to have normal myelograms. These intervals are generally lower than those previously reported for childhood, but we believe this results from a more rigid selection of the control group. In addition, artifactual increases in concentrations of free neurotransmitters, caused by breakdown of amino acid conjugates, are minimized by (a) immediate freezing of the CSF samples to prevent enzyme-mediated changes, (b) omission of a deproteinization step, and (c) precolumn derivatization to reduce on-column breakdown of amide and peptide forms.

Amino Acids↗
PubMed1988

Determination of amino acids in different regions of the rat brain. Application to the acute effects of tetrahydrocannabinol (THC) and trimethyltin (TMT).

A modified HPLC method is described for the determination of amino acids [aspartic acid, glutamic acid, glutamine, glycine, taurine, and gamma-aminobutyric acid (GABA)] in brain tissue utilizing precolumn derivatization with o-phthalaldehyde (OPA)-tert-butyl-thiol and electrochemical detection. A simple extraction procedure was employed and DL-homoserine used as internal standard. A neurotoxin previously shown to affect brain amino acids (trimethyltin, TMT) and a psychoactive compound hypothesized to act on these neurochemicals (delta-9-tetrahydrocannabinol, THC) were administered to adult male rats and amino acids were measured. Results revealed a gradient of distribution of most amino acids, with lowest levels posteriorly in the brain stem and increasing to the highest values in anterior cortical regions. TMT increased glutamine significantly in all brain regions examined, but increased glycine and decreased taurine only in the frontal cortex and hippocampus. No significant changes in any amino acid were found in hippocampus after THC treatment. The results establish the validity and usefulness of this HPLC method for detecting neurotoxicity-related changes in brain amino acid metabolism.

Amino Acids↗
PubMed1975

Glucose utilization by the salivary glands of the marmoset Saguinus oedipus.

Glucose utilization by the marmoset salivary glands was studied radioisotopically, both in vitro and in vivo. Surgically excised, minced parotid and submandibular glands from 7 adult animals were incubated in vitro in a medium containing uniformly labeled 14C glucose (glucose-UL-14C), then subjected to respirometry measurements and to extraction and separation procedures for the radioautographic isolation and identification of amino acids, organic acids, and glucose. Glucose utilization in vivo by the marmoset salivary glands was determined in 3 animals by analysis for 14C-containing amino acids, organic acids and glucose in pilocarpine-stimulated whole saliva, following intraperitoneal injection of glucose-UL-14C. The whole saliva was fractionated, separated and processed for localization of radioactivity by the same methods that were used in the in vitro studies. The isolated and in situ salivary glands converted glucose-UL-14C into 14C-containing carbon dioxide, glycine, alanine, glutamic acid, aspartic acid, and lactate. In no instance did the amount of 14C-glucose secreted in saliva exceed 0.52 mg/100 ml..

Amino Acids↗
PubMed1998

Analysis of the free amino acid content in pollen of nine Asteraceae species of known allergenic activity.

The study reports the free amino acid composition of the pollen of nine members of the family Asteraceae, i.e. Ageratum conyzoides L., Blumea oxyodonta DC., Eupatorium odoratum L., Gnaphalium indicum L., Mikania scandens Willd., Parthenium hysterophorus L., Spilanthes acmella Murr., Vernonia cinerea (L.) Lees. and Xanthium strumarium L. by thin layer chromatography. The amino acid content was found to vary from 0.5-4.0% of the total dry weight. Fourteen amino acids were identified, among which amino-n-butyric acid, aspartic acid and proline were present in almost all pollen samples. The other major amino acids present in free form included arginine, cystine, glutamic acid, glycine, isoleucine, leucine, methionine, ornithine, tryptophan and tyrosine.

Amino Acids↗
PubMed1999

Immuno-, phagocytosis-modulating and antitoxic properties of dipeptides are defined by the activity of their constituent amino acids.

In experiments on mice and the influence in vitro of the dipeptides GluTrp, LysAsp, LysVal, AspGlu, GluAsp on their constituent amino acids and mixtures on the indexes of specific and non-specific resistance was studied. There is no difference between the dipeptides and their constituent amino acids (excepting Lys) neither in immune, phagocytosis modulating or antitoxic properties. Some amino acids (aspartic acid, glutamic acid, methionine and tryptophan) are promising for the effective prevention of diseases that develop as a result of chronic benzene intoxication.

Amino Acids↗
PubMed1957

The nutrition of animal tissues cultivated in vitro. IV. Amino acid requirements of chick embryonic heart fibroblasts.

1. The amino acid requirements of freshly explanted chick embryonic heart tissues cultivated in completely synthetic media have been determined, employing a nutritional depletion technique. Arginine, histidine, lysine, tyrosine, tryptophan, phenylalanine, cystine, methionine, threonine, leucine, and valine were found to be essential. Serine, isoleucine, glycine, and glutamine were found to be non-essential. Glutamic acid, aspartic acid, alpha-alanine, proline, and hydroxyproline were found to be inhibitory in this test system. 2. A total amino acid level of approximately 100 mg. per cent was found to be optimal and DL-amino acids were found to be non-toxic, unless used in high concentrations. 3. A comparison has been made of the amino acid requirements of various types of tissue cultures, of the chick, and of man and certain differences in these requirements have been discussed.

Alanine↗
PubMed1983

Acute amino acid nephrotoxicity.

Previous clinical and experimental data suggest that a limited number of AAs with particular molecular characteristics can adversely affect renal function. The present investigation was conducted to better define the scope and the molecular basis of this nephrotoxicity. Sprague-Dawley rats (N = 31) undergoing a solute diuresis were subjected to 80 min infusions (125 mumol/kg/min) of cationic AAs (lysine, arginine), anionic AAs (glutamic acid, aspartic acid), or neutral AAs (alanine, glycine). Rats infused for 80 min with equimolar amounts of urea or dextrose served as controls (N = 8). GFR (Cioth) were measured 40 min before, during, and 140 min after these infusions. Albumin excretion rates were determined by radioimmunoassay. All AA infusates induced significant (p less than 0.001) reductions in GFR compared to the control infusates (cationic AAs: 62% +/- 4; anionic AAs: 57% +/- 5; neutral AAs: 33% +/- 1; controls: 8% +/- 4) (X +/- S.E.M.). However, only cationic AAs induced a significant increase in albumin excretion (360% +/- 72; p less than 0.001). AA-treated rats had histologic changes with mild tubular injury compared to control rats. These data indicate the following. (1) AAs have in common a nephrotoxic potential. (2) This nephrotoxicity arises, in part, from the nonvariable portion of AA molecules since glycine, which has no variable (R) group, induced a significant reduction in GFR (32% +/- 1). (3) The ability of AAs to decrease GFR is enhanced by certain R groups. However, R group charge is not a critical factor in producing this response. (4) AA-induced increments in albumin excretion and reductions in GFR must arise via independent mechanisms. Since AA infusions are commonly used in patients with ARF the possibility that such therapy might have a deleterious effect on renal function and on the subsequent recovery from ARF should be entertained.

Acute Kidney Injury↗
PubMed1986

Fractionation and amino acid composition of an aspartic acid-containing thermal proteinoid population.

The heterogeneity of an aspartic acid-containing thermal polymer population has been studied by anion exchange chromatography, amino acid analysis of the resulting fractions and data processing by the principal components method. By using stepwise or continuous gradients of ionic strength both saw-toothed or bell-shaped elution profiles were obtained. This behaviour and the amino acid composition of analyzed fractions suggest a relatively high degree of heterogeneity in the polymer population although less than theoretically expected. This conclusion is compared with the findings reported in proteinoids made by similar procedures.

Amino Acids↗
PubMed2001

Vasorelaxation induced by L-glutamate in porcine coronary arteries.

Isolated porcine coronary arteries (PCA) contracted by depolarization with high K0 or by histamine (10 microM) were relaxed concentration-dependently by glutamic acid, aspartic acid, N-methyl-D-aspartate (NMDA) and, gamma-aminobutyric acid (GABA). In the PCA preparations contracted by high K0 or histamine the effects were monophasic, but the histamine-induced effects were more sustained and of larger amplitude. The ED50 values of cumulative concentration-response (CCR) curves obtained for the relaxation induced by L-glutamate in histamine-stimulated PCA preparations were shifted from 0.8 mM to 0.25 microM in presence of 1 mM glycine, a co-agonist required for the activation of NMDA receptors. The relaxations resulting from low-affinity binding of L-glutamic were dependent on Ca0 as evidenced by the shift of CCR curves to the right in the presence of 5-100 mM K0. In contrast, CCR curves obtained for contractions induced by NaF (1.5-12 mM), were significantly shifted to the left (from 6.3 to 3.1 mM). A depression of the maximum effect observed at higher F- concentrations was reversed by addition of 5 mM Mg0. Data show that glutamate induces a vasorelaxation that may be associated with symptoms seen in Chinese restaurant syndrome.

Animals↗
PubMed2005

[Detection of amino acid neurotransmitters in cerebrospinal fluid of patients in persistent vegetative state].

OBJECTIVE: To detect the amino acid neurotransmitters in cerebrospinal fluid of patients in persistent vegetative state (PVS) to define their relation to the clinical manifestations of the patients. METHODS: The cerebrospinal fluid from 46 patients in PVS and 20 control patients were collected for detection of glutamic acid, aspartic acid, alanine and glycine by high-performance liquid chromatography. RESULTS: All the four amino acids were separated by chromatography within 25 min. The contents of all the 4 neurotransmitters in PVS group were higher than those in the control group, and their contents were inversely correlated to PVS score of the patients. The differences in the concentration of glycine and alanine were significant between PVS patients and the control patients (P<0.05). CONCLUSION: The patient's clinical manifestations are related to the contents of amino acid neurotransmitters in the cerebrospinal fluid of PVS patients.

Adolescent↗
PubMedDate not supplied

Contribution of temperature gradient to aggregation of thermal heterocopolymers of amino acids in aqueous milieu.

We prepared thermal heterocopolymers of amino acids, aspartic acid and proline, and solubilized them in distilled water at boiling temperature. The resulting suspension was then cooled down while controlling the cooling rate. The maximum growth of phase-separated microspheres was found to occur at a finite, nonzero cooling rate. Temperature-gradient controlled growth of these microspheres indicates that aggregation of thermal heterocopolymers of amino acids in their aqueous milieu is irreversible. In view of the fact that evolutionary process is an indication of lasting physical irreversibility, thermal heterocopolymers of amino acids were shown to have an evolutionary significance in maintaining the capacity of irreversibility lasting over at least several hours.

Aspartic Acid↗
PubMed1980

[New placental protein (PP15) with immunosuppressive properties (author's transl)].

The isolation and characterization of a new placental protein (PP15) which has immunosuppressive properties are described. The protein was purified from extracts of human term placentae by rivanol and ammonium sulfate fractionation, gel filtration, ion exchange chromatography, preparative zone electrophoresis, and chromatography on hydroxyapatite. PP15 was found to have a sedimentation coèfficient of 2.9 S and a molecular weight of 30,700 daltons as determined by ultracentrifugation; its molecules apparently are composed of two identical subunits which are held together by non-covalent bonds. The electrophorectic mobility of PP15 corresponds to that of albumin. PP15 is a glycoprotein and contains 3.3% carbohydrates (hexoses 2.8%, hexosamines 0.3%, sialic acid 0.2%). The amino acid composition of this protein was also determined: the most abundant amino acids in the peptide chain were found to be glutamic acid, aspartic acid, isoleucine, and leucine. PP15 has immunosuprressive properties: on testing its effect on the lymphoycte transformation in the MLC-test in vitro a significant inhibitory activity could be demonstrated.

Aspartic Acid↗
PubMed1986

Glutamic acid as a putative transmitter of the interhemispheric corticocortical connections in the rat.

The effect of hemidecortication on the endogenous levels of amino acids in medial, sulcal, and dorsal frontal cortex as well as in parietal, temporal, and occipital cortex of the rat was investigated. Under aseptic conditions, the right cerebral cortex was aspirated by suction. Then, 21 days later, the content of glutamic acid, aspartic acid, gamma-aminobutyric acid, glycine, serine, threonine, and alanine was analyzed in six areas of the intact contralateral cortex using GLC. The results demonstrated a specific decrease in the endogenous levels of glutamic acid in both parietal and temporal cortex after hemidecortication of the contralateral side. This finding suggests that glutamic acid may serve as a neurotransmitter for some of the interhemispheric corticoparietal and corticotemporal fibers. In a follow-up experiment, the effect of a frontal lesion on the endogenous levels of the same amino acids in the striatum was also examined. In this case, the glutamic acid content exhibited a decrease of 31% relative to the control value. This observation confirms the earlier finding of a glutamate-containing pathway from the frontal cortex to the striatum.

Alanine↗