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PubMed1991

Estimation of ages from racemization of an amino acid in teeth--assessment of errors under various experimental conditions.

In order to estimate ages of corpses more accurately from racemization of an amino acid (aspartic acid) in the dentine of teeth, errors resulting from various experimental conditions were assessed. The factors included for evaluation were: the sample weight, time and temperature of hydrolysis, concentration of hydrochloric acid, and the volume of the hydrochloric acid solution, each of which might have effect on resulting errors. This study revealed that alteration of the sample weight did not change the D/L ratio and that the estimated age remained constant as long as the sample weight was within the range of 3 mg and 50 mg. However, with the remaining factors, the D/L ratio changed with the alteration of conditions. The correlation can be represented by a straight line in a graph, which is a sign of the first order reaction. The coefficients of correlation were between 0.972 and 0.999, indicating their extremely high correlation with the D/L ratio. The errors expressed in estimated age values per unit of variables were: 0.02 years/min. for a time (min.) of hydrolysis; 1.5 years/degrees C for temperature of hydrolysis; 0.5 years/0.1 N (normal) for concentration of hydrochloric acid; and 0.6 years/ml for the volume of hydrochloric acid solution. Consequently, the temperature of hydrolysis was found the most influential. Alteration of values of the other four factors did not largely affect the estimation.

Age Determination by Teeth↗
PubMed1990

[Chemical studies on polysaccharide of Achyeanthes bidentata].

A peptide-polysaccharide, ABAB showing immunological activity was isolated from Achyeanthes bidentata Bl. It was shown to be homogeneous by HPLC and optical rotation analysis. Its molecular weight was estimated to be 2.3 x 10(4). It composed of D-glucuronic acid, D-galactose, D-galacturonic acid, L-arabinose and L-rhamnose in molar ratio of 12:2:3:1:1. Reduction of carboxyl groups, methylation analysis, periodate oxidation, Smith degradation and IR analysis showed that ABAB possesses a main chain composed of (1----4)-D-glucuronic acid and (1----4)-D-galacturonic acid residues. The non-reducing terminal residues in the side chains were L-arabinose and L-rhamnose. ABAB contained 24.1% of peptides composed of glycine, glutamic acid, aspartic acid and serine.

Drugs, Chinese Herbal↗
PubMed1990

Behavioral deficits in rats with minimal cortical hypoplasia induced by methylazoxymethanol acetate.

Methylazoxymethanol, a short-acting antimitotic agent, produces marked cortical hypoplasia in fetuses when injected into pregnant rats. These offspring also have increased cortical concentrations of biogenic amines associated with hyperactivity and learning deficits. In this experiment, rats with a relatively mild degree of methylazoxymethanol-induced cortical hypoplasia were studied to determine whether these neurochemical and behavioral abnormalities persisted. Sprague-Dawley pregnant rats were injected intraperitoneally on day 15 of gestation with methylazoxymethanol acetate (25 mg/kg). Total brain weight was reduced by 12% and cortical slab weight by 28% in methylazoxymethanol-exposed offspring. They were more active than control rats and showed a trend toward slower learning in a swim maze. Affected offspring had increased cortical concentrations of norepinephrine, 5-hydroxyindoleacetic acid, and glycine. There was no significant difference in the concentrations of serotonin gamma-aminobutyric acid, aspartic acid, glutamic acid, or glutamine. Methylazoxymethanol-lesioned animals with mild cortical hypoplasia remained measurably hyperactive and may serve as a model for the study of neurotransmitter and neuropathologic abnormalities associated with hyperactivity in children with microcephaly.

Animals↗
PubMed1978

Hydroxyapatite-reactive salivary protein revealed by iso-electrofocusing electrophoresis.

Salivary protein involvement in the formation of acquired enamel pellicle, so far, has been discussed in terms of hydroxyapatite (HA)-reactive salivary proteins only from the parotid gland. This study was undertaken to seek this type of protein in the human whole (mixed) saliva and to investigate its normal and pathological variations. Several kinds of hydroxyapatite, either biogenous or synthesized by solid phase reaction, were used as a powder (250 mesh). HA was incubated with concentrated whole saliva at 25 degrees for 30 min. After centrifugation and filtration salivary proteins were analysed on a Multiphor isoelectrofocusing gel electrophoresis. The control salivary proteins were separated into three major groups; acidic (A1-A8), neutral neutral (N1-N4), and basic (B1-B3) isoelectric point (pI). In the HA incubated sample, one of the major neutral bands (NI) preferentially disappeared at about pI 7.5. This NI band was missing or scarce in the parotid saliva and had an amino acid composition rich in glycine, lysine, serine, glutamic acid, aspartic acid, and histidine. This protein was considered to be one of the major HA-reactive proteins in human whole saliva.

Adsorption↗
PubMed1989

Safety of long-term large doses of aspartame.

Safety of long-term administration of 75 mg/kg of aspartame per day was evaluated with the use of a randomized, double-blind, placebo-controlled, parallel-group design in 108 male and female volunteers aged 18 to 62 years. Subjects received either aspartame or placebo in capsule form three times daily for 24 weeks. No persistent changes over time were noted in either group in vital signs; body weight; results of standard laboratory tests; fasting blood levels of aspartame's constituent amino acids (aspartic acid and phenylalanine), other amino acids, and methanol; or blood formate levels and 24-hour urinary excretion of formate. There also were no statistically significant differences between groups in the number of subjects experiencing symptoms or in the number of symptoms per subject. These results further document the safety of the long-term consumption of aspartame at doses equivalent to the amount of aspartame in approximately 10 L of beverage per day.

Adolescent↗
PubMed1988

[Effect of natural or synthetic detergents on the transport of D-glucose in the membranes of vesicles of the brush border of the intestine of the rabbit].

We describe here the effects of natural and synthetic detergents on the D-glucose transport into brush-border membranes of vesicles of rabbit's intestine. Two synthetic detergents: Triton X-100 and dodecyltrimethylammonium bromide have been found very strong inhibitors (more than 50 p. 100 of inhibition of maximal D-glucose uptake). Kinetic studies showed that these detergents behaved as mixed type inhibitors. The Na+-dependent transport of amino acids (aspartic acid, lysine, phenylalanine) is only poorly affected by dodecyltrimethylammonium bromide, while Triton X-100 inhibits unspecifically all the transport studied.

Animals↗
PubMed1979

Effect of human plasma apolipoproteins on the activity of purified lecithin: cholesterol acyltransferase.

An active preparation of lecithin: cholesterol acyltransferase (LCAT, EC 2.3.1.43) was isolated from human plasma by density ultracentrifugation, high-density lipoprotein affinity chromatography, DEAE-Sepharose and hydroxylapatite chromatography. This enzyme preparation gave a single band on polyacrylamide gel electrophoresis in 8 M urea and on sodium dodecyl sulfate gel electrophoresis. Upon analytical isoelectric focusing the enzyme separated into at least five isoforms with isoelectric points ranging from 5.1 to 5.5. The enzyme with an apparent molecular weight of 66,000 +/- 2,000 was characterized by a high content of glutamic acid, aspartic acid, leucine and glycine and contained approximately 31 moles of glucosamine/10(3) moles of protein and no galactosamine. The purified enzyme, stored at 20-40 microgram/ml at 4 degrees C, had a half-life of 26 +/- 4 days. The effect of purified human plasma apolipoproteins A-I, A-II, C-I, C-II, C-III and D on the activity of purified LCAT was studied, using egg-yolk lecithin (40 microM): cholesterol (10 microM) vesicles prepared in 1.25% ethanol in the absence or presence of 0.5% albumin. Addition of albumin to the incubation mixture nearly doubled the esterification rate of LCAT with A-I as activator (n=4), whereas it inhibited esterification by approximately 35% (n=3) if C-I was the activator. Maximum activation by C-I yielded only 13 +/- 6% (vesicles with albumin) or 42 +/- 5% (vesicles without albumin) of the LCAT activity obtained with A-I. Each of the apoproteins A-II, C-II, C-III and D inhibited the LCAT reaction in the presence of A-I or C-I at concentrations needed for maximal activation. Contrary to previous work, apolipoprotein D does not appear to be an activator of LCAT. LCAT activity is significantly affected by albumin and the apolipoproteins A-II, C-II, C-III, and D.

Amino Acids↗
PubMed1977

[Low molecule and middle molecule metabolites with haemodynamic activity in the ultrafiltrate from uraemic patients (author's transl)].

Substances causing blood pressure changes and myocardial damage in rats were first detected in the ultrafiltrate obtained from patients on long-term haemodialysis by means of size separation, high-voltage electrophoresis and thin-layer chromatography. Of the 100 to 140 fractions produced by Sephadex G 15 chromatography at least 3 raised the blood pressure when administered in doses of 2 to 10 mg/0.1 to 0.2 ml 0.9% NaCl, that is the high molecular fraction 18 to 23 and the low molecular fractions 71 to 72 and 73 to 74. The fractions 96 to 98 and 97 to 106 showed high toxicity. Less than 1 mg/0.1 to 0.2 ccm 0.9% NaCl produced cardiac arrest. The fractions 35 to 55, which originate from the middle molecules and are retained in regularly uraemia, contain substances which caused a reduction in blood pressure at low dosage and cardiotoxic effects at a dosage of more than 10 mg. Thin-layer chromatography indicates that the substances most probably consist of peptides whose structure contains the amino acids leucine, isoleucine, valine, glutamic acid, aspartic acid, alanine and cystine.

Humans↗
PubMed1980

Phenol-extracted lipopeptidopoly-saccharide (LPPS) complex from Listeria monocytogenes.

Endotoxin phenol extraction method with subsequent ultracentrifugation and/or chromatographic analysis on Sepharose 2 B column were used to obtain biologically active isolate that turned out to contain polysaccharide, peptide and lipid fractions. The raw phenol extract formed 15% and the LPPS complex, obtained from it by ultracentrifugation, 0.17% of bacterial biomass. The LPPS complex contained 11 amino acids representing about 11% of its dry weight. Similarly as in factor Ei and in analogous extracts isolated by other authors the prevailing amino acids were glutamic acid, aspartic acid and lysine. The LPPS complex contained 1.26% of hexosamine, further hexoses, methyl pentoses and ribose. KDO was not detected. Further this complex consisted of 3% of freely-bound and 5% of firmly-bound lipids, beta-hydroxymyrist acid was not detectable. The composition of fatty acids in the firmly-bound lipid fraction of the LPPS complex differed quantitatively from that both in factor Ei and bacterial cell bodies. The tightness of lipid bonds during purification and the biological role of the Listeria lipids are discussed. On the basis of detected chemical and biological properties, both compatible and incompatible with peptidoglycan, a specific character of endotoxin-like isolates from L. monocytogenes is assumed.

Amino Acids↗
PubMed1983

Angiotensinogen.

Human angiotensinogen has been purified from outdated blood bank plasma. The purified angiotensinogen has a specific angiotensin I (Ang I) content of 20.7 micrograms Ang I/mg protein and contains only one amino-terminal amino acid, aspartic acid. However, it exhibits two bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with apparent molecular weights of 61,400 and 65,400. It is concluded that these bands represent different forms of angiotensinogen because the specific Ang I content is equivalent to the theoretical Ang I content. Analysis of the purified angiotensinogen showed it to contain 14% carbohydrate.

Amino Acid Sequence↗
PubMedDate not supplied

[Nitrous compound content in the tissues of the cerebral hemispheres and cerebellum of rats after a flight on the Kosmos-1129 biosatellite].

The content of ammonia, glutamine, urea, glutamic acid, aspartic acid, and GABA was measured to study nitrogen metabolism. Soon after recovery (6-10 hours after recovery) the content of the above compounds in brain tissues increased, except for GABA whose content decreased. Similar but more marked changes were seen in the brain of control rats exposed to a repeated immobilization stress-effect. These changes were still greater in the flight rats exposed to a repeated immobilization stress-effect postflight. It is suggested that the postflight changes of the above parameters of nitrogen metabolism are induced by stress-agents inherent in space flight and recovery.

Animals↗
PubMed1978

[Participation of glutamate and alanine in amino acid biosynthesis, in lipogenesis, and in gluconeogenesis in the brain].

The participation of glutamate and alanine in lipogenesis and gluconeogenesis of brain was investigated. 5(14)C glutamate was injected intracisternally in an amount of 5 mcCu/l g tissue and 3(14)C-alanine was injected subcutaneously 30 mcCu/100 g body weight. Labels from glutamate and alanine were recovered in different lipid franctions -- in phospholipids, glycerides, free fatty acids and cholesterol, as well as in glucose and glycogen. An intensive incorporation of label from 5(14)C glutamate into various amino acids--aspartic acid, glutamine, serine, glycine and alanine--was demonstrated. The data presented indicate the participation of amino acids in lipogenesis and gluconeogenesis of brain.

Alanine↗
PubMed1976

[Problems of long-term parenteral feeding in childhood (author's transl)].

Long-term parenteral feeding in childhood must be adapted to the requirements of the young organism. The caloric requirements are mainly provided by glucose and fat emulsions; additional calories can be supplied by xylite and, with some reservations, by fructose. For neonates and young infants the combination and quantity of amino-acids is of particular importance: histidine, arginine, proline and tyrosine are essential amino-acids; glycine, glutamic acid, aspartic acid and cystine should form part of the unspecific sources of nitrogen. Addition of trace elements and vitamins is obligatory in long-term parenteral feeding. Complications may arise at the site of the catheter (sepsis, clotting). Late damage due to intravenous feeding is known to occurs; but a more detailed knowledge needs long-term investigations.

Amino Acids↗
PubMed1993

The importance of specific gamma-carboxyglutamic acid residues in prothrombin. Evaluation by site-specific mutagenesis.

Prothrombin has 10 gamma-carboxyglutamic acid residues which are essential for the metal ion binding properties and membrane binding function of the protein. To assess the importance of each gamma-carboxyglutamic acid residue we made, by site directed mutagenesis, a series of mutant human prothrombins each with a single glutamic acid to aspartic acid substitution at positions 6, 7, 14, 16, 19, 20, 25, 26, 29, or 32 which are gamma-carboxylated in native prothrombin. Along with wild-type prothrombin, the prothrombin mutants were expressed in Chinese hamster ovary cells, purified by immunoaffinity chromatography using polyclonal anti-prothrombin antibodies, and shown by amino acid analysis to contain the expected number of gamma-carboxyglutamic acid residues. Only substitution of gamma-carboxyglutamic acid 6 with aspartic acid yields a protein with procoagulant activity, affinity for phospholipid and KM(app) for prothrombinase indistinguishable from wild-type prothrombin. In contrast, the conservative gamma-carboxyglutamic acid to aspartic acid mutation at positions 16, 26, or 29 results in proteins with little or no procoagulant activity, Kd(app) for binding to phospholipid at least 200-fold higher than wild-type prothrombin and a KM(app) for interaction with the prothrombinase complex nearly 100-fold higher than wild-type prothrombin. The mutations at residues 7, 14, 19, 20, 25, or 32 yielded proteins with intermediate procoagulant activities, between 15 and 52% of wild-type prothrombin. These data have been interpreted to suggest that there are certain gamma-carboxyglutamic acid residues which are important to maintaining the basic structure of the calcium-liganded Gla domain while other gamma-carboxyglutamic acid residues subserve other functions including membrane binding and interdomain interactions.

1-Carboxyglutamic Acid↗
PubMed1993

Cloning and characterization of complementary DNA encoding the eukaryotic initiation factor 2-associated 67-kDa protein (p67).

The eukaryotic initiation factor 2 (eIF-2)-associated 67-kDa glycoprotein (p67) protects eIF-2 alpha-subunit from inhibitory phosphorylation by eIF-2 kinases, such as heme-regulated inhibitor and double-stranded RNA-activated inhibitor. This promotes protein synthesis in the presence of eIF-2 kinases present in animal cells (Ray, M. K., Datta, B., Chakraborty, A., Chattopadhyay, A., Meza-Keuthen, S., and Gupta, N. K. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 539-543). In this study, the primary structure of rat p67 is determined by cDNA cloning. Based on the partial amino acid sequences of overlapping tryptic and cyanogen bromide cleaved fragments, degenerate oligonucleotides were synthesized and used as primers for the polymerase chain reaction to amplify the corresponding p67 cDNA fragment from rat liver first strand cDNA. The amplified DNA was then used as a probe to screen a rat tumor hepatoma (KRC-7) cDNA library, and a positive clone covering the entire coding region was obtained. From the cDNA sequence, an open reading frame that encodes p67 as a 480-amino acid protein with a molecular mass of 53 kilodaltons was predicted for the unglycosylated protein. The cloned cDNA was further characterized by in vitro transcription-coupled translation in micrococcal nuclease-treated reticulocyte lysate. The translated product migrated similarly to p67 in SDS-polyacrylamide gel electrophoresis and was precipitated with antibodies against p67. Northern blot analysis of rat liver poly(A)+ RNA showed a single size class (approximately 2 kilobases) of mRNA. The deduced amino acid sequence of the protein showed a highly charged N-terminal region composed of two basic polylysine blocks and an acidic aspartic acid block. The protein also exhibits significant sequence identity in the N-terminal region with human eIF-2 beta-subunit.

Amino Acid Sequence↗
PubMed1996

An unusual dehalogenating peroxidase from the marine terebellid polychaete Amphitrite ornata.

The terebellid polychaete Amphitrite ornata produces no detectable volatile halogenated secondary metabolites, but frequently inhabits coastal marine sediments heavily contaminated with anthropogenic or biogenic haloaromatic compounds. This animal contains high levels of two very unusual enzymes, dehalogenating peroxidases. We have purified and partially characterized one of these dehaloperoxidases, DHP I. DHP I is a heme enzyme (Mr = 30,790) composed of two identical subunits (Mr = 15,529) and is very rich in the amino acids aspartic acid (+ asparagine) and glutamic acid (+ glutamine). The enzyme converts trihalogenated phenols, such as 2,4,6-tribromophenol, into dihalogenated quinones. The optimum pH for this reaction is 5.0. DHP I is also active against di- and monohalogenated phenols and will oxidize bromo-, chloro-, and fluorophenols. We have identified similar dehaloperoxidase activities in other infaunal polychaetes, including halometabolite-producing species.

Amino Acids↗
PubMed1996

Motility and agglutination of fowl spermatozoa in media of different amino acid content and pH value in vitro.

The objective of the present experiments was to study some properties of fowl spermatozoa which may play a role in the sperm storage and emptying mechanism of the uterovaginal sperm storage tubules (SST) of the hen. The effects exerted by different amino acids (aspartic acid, Asp; glutamic acid, Glu; gamma-aminobutyric acid, GABA; glycine, Gly) and by the pH of the environment at 24 and 39 degrees C on the motility and agglutination of cock spermatozoa were studied in vitro. The spermatozoa did not show agglutination in the presence of Asp and Glu, and became immobilised if the concentration of Glu or the acidity of the environment was increased. In neutral solutions of GABA and Gly or in a faintly alkaline solution characteristic plait-like conglomerations could be seen. The motility of spermatozoa immobilised by Glu could be restored in a varying degree by the addition of GABA or Gly. At a temperature of 24 degrees C, the spermatozoa became immobilised in a medium of pH 6.0 while showed maximum motility at pH 7.1. At 39 degrees C, the spermatozoa were immobilised at higher pH (6.2) and required a pH value as high as 7.4-7.5 to show the highest motility. Spermatozoa inactivated in an acidic solution could be immediately mobilised by alkalisation of the medium, irrespective of the Ca2+ content of the solution. Thus, Ca2+ was not found to play a role in the reactivation of spermatozoa. Nevertheless, marked differences were observed in the maintenance of sperm motility between solutions either containing or lacking Ca2+. As the concentration changes of the above-mentioned amino acids and the pH changes were found to affect the motility and agglutination of spermatozoa in vitro, they may influence also the regulatory mechanism of the uterovaginal SST during the egg-formation cycle in vivo.

Amino Acids↗
PubMed1977

Renal glucosuria and aminoaciduria.

A follow-up examination of five patients in whom renal glucosuria had been diagnosed 7-15 years previously, showed that the condition was unchanged. There was no indication of hormonal abnormalities. Oral glucose tolerance test, with determination of insulin, growth hormone and free fatty acids, showed no difference between the patients and a group of normal subjects. The urinary excretion of insulin and albumin was normal, but two patients turned out to have an increased excretion of certain amino acids, aspartic acid in one and glutamic acid, citrulline and alanine in the other.

Adult↗