Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This paper reports a study of changes in red blood cell enzymes and some serum parameters during and after treatment of protein-calorie malnutrition. The red cell GSH levels were low during the crisis, together with the levels of GSSG:NADPH reductase, GSH:H2O2 peroxidase, aspartate aminotransferase and alanine aminotransferase. After treatment the levels of all these enzymes increased significantly to normal values. Of the serum parameters investigated, significant reduction in the activity of the enzymes cholinesterase, catecholamine oxidase, total proteins, albumin, urea and electrolytes were obvious, and returned to normal values after treatment. Ceruloplasmin activity remained low even after three weeks' treatment and could not be related to copper levels. The results are discussed in relation to anemia and liver damage that may accompany the syndrome.
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PMID:Protein-calorie malnutrition: a study of red blood cell and serum enzymes during and after crisis. 82 Apr 94

The pontine nuclei form the key relay nuclei in the cerebropontocerebellar pathway. Although a great deal of information is available regarding the anatomy of this region, the identity of the neurotransmitter(s) contained in the neurons of the pontine gray are not known. The aim of the present investigation is to utilize immunohistochemical techniques to determine whether glutamate, a putative excitatory transmitter, and the enzymes responsible for its metabolism, are found in pontine neurons. Both glutaminase, an enzyme which converts glutamine to glutamate, and aspartate aminotransferase, an enzyme which is involved in the interconversion between glutamate and aspartate, have been proposed to be markers of neurons which use excitatory amino acids as neurotransmitters. The present study utilizes a monoclonal antibody against carbodiimide-fixed glutamate and polyclonal antisera against glutaminase and aspartate aminotransferase in conjunction with the indirect peroxidase technique or the peroxidase-labeled biotin-avidin procedure to localize glutamatergic neurons in the pontine nuclei of the rat. Numerous neurons in all subdivisions of the pontine nuclei were found to contain carbodiimide-fixed glutamate-like immunoreactivity, glutaminase-like immunoreactivity or aspartate aminotransferase-like immunoreactivity. Horseradish peroxidase was injected into the cerebellum of four rats for use with a combined retrograde transport-immunohistochemical procedure. Double-labeled neurons were observed in all subdivisions of the pontine nuclei, indicating that pontine neurons which contain glutamate-like immunoreactivity project to the cerebellum. Based on the hypothesis that increased levels of glutamate, glutaminase and aspartate aminotransferase reflect a transmitter role for glutamate, the present data raise the possibility that glutamate may be a major neurotransmitter of pontocerebellar fibers.
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PMID:Immunohistochemical localization of glutamate, glutaminase and aspartate aminotransferase in neurons of the pontine nuclei of the rat. 242 96

We have previously shown that the rapid clearance of intravenously injected lactate dehydrogenase M4 from plasma is mainly due to endocytosis by macrophages in liver, spleen, and bone marrow. We have now studied endocytosis of lactate dehydrogenase M4 in detail, using freshly isolated rat liver macrophages (Kupffer cells) in vitro. 125I-lactate dehydrogenase M4 rapidly accumulated in the cells and was subsequently degraded to trichloroacetic acid-soluble material. Degradation was inhibited by leupeptin, an inhibitor of lysosomal proteases. Breakdown of the protein was also greatly diminished by treatment of the cells with chloroquine, a weak base which inhibits proteolysis by raising the pH in endosomes and lysosomes. High concentrations of chloroquine inhibited uptake. Lactate dehydrogenase M4 was not endocytosed by liver endothelial cells, although, under the same conditions, these cells were shown to accumulate horse radish peroxidase via a mannose-specific receptor. Uptake of lactate dehydrogenase M4 by Kupffer cells was strongly reduced after pretreatment of the cells with low concentrations of proteases. Endocytosis of lactate dehydrogenase M4 exhibited saturation kinetics (Km = 0.8 microM) and was competitively inhibited by mitochondrial and cytosolic malate dehydrogenase, alcohol dehydrogenase, adenylate kinase, and creatine kinase MM, enzymes which are rapidly cleared in vivo. Enzymes with long half-lives in plasma, namely lactate dehydrogenase H4, alanine aminotransferase, and cytosolic aspartate aminotransferase did not compete at concentrations up to 10 microM. Our results indicate that Kupffer cells contain a receptor that is involved in the clearance of lactate dehydrogenase M4 and a number of other tissue-derived enzymes from plasma. Uptake of lactate dehydrogenase M4 does not occur via a receptor that recognizes carbohydrate residues, for the enzyme is not a glycoprotein.
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PMID:Receptor-mediated endocytosis of lactate dehydrogenase M4 by liver macrophages: a mechanism for elimination of enzymes from plasma. Evidence for competition by creatine kinase MM, adenylate kinase, malate, and alcohol dehydrogenase. 282 Sep 61

Molecular mass, Stoke's radius, frictional coefficient and isomer-type of non-denatured proteins can be obtained by time-dependent gradient gel electrophoresis by evaluating the resulting data using a two-step mathematical procedure. Provided a histochemical staining procedure is available to locate the position of an enzyme in the gel, crude cell extracts can be used for estimating their molecular size properties. The computation of molecular properties of non-denatured proteins is demonstrated for isozymes of aspartate aminotransferase (EC 2.6.1.1), peroxidase (EC 1.11.1.42) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) from current-year needles of spruce. The resulting data as well as those which were calculated for esterase (EC 3.1.1.1), glutamate dehydrogenase (EC 1.4.1.4), isocitrate dehydrogenase (EC 1.4.1.42), and shikimate dehydrogenase (EC 1.1.1.25) are in accordance with those reported in the literature. The method described may be applied to various scientific areas such as genetics or environmental pollution. It could be shown here that current-year needles of injured spruce (damage class 3) contained two more peroxidase isozymes and one more glucose-6-phosphate dehydrogenase isozyme than those from non-injured trees. These differences may mark two genotypes of spruce of different susceptibilities towards present-day air and soil pollutants.
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PMID:Determination of molecular mass, Stokes' radius, frictional coefficient and isomer-type of non-denatured proteins by time-dependent pore gradient gel electrophoresis. 323 69

Two specific and sensitive immunoassay methods for the determination of mitochondrial aspartate aminotransferase (m-AST) are described. One is a sandwich enzyme immunoassay which measures immunologically active m-AST using polystyrene balls coated with anti-m-AST antibody and peroxidase-labelled anti-m-AST antibody as the second antibody. The detection limit of this assay was 10 micrograms/l. The other is a paper disk method which measures catalytically active enzyme bound to anti m-AST antibody-conjugate paper disks. The calibration curve was linear up to 250 U/l. These assay methods were used to monitor the level of m-AST in serum. From measurements obtained by both methods, the correlation between the concentration of m-AST protein and its activity was poor (liver diseases, r = 0.539; myocardial infarction, r = 0.774) confirming that an inactive form of m-AST exists in serum, and that the specific activity of serum m-AST differs in individual diseases.
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PMID:Determination of mitochondrial aspartate aminotransferase in serum. 351 1

A sensitive and specific sandwich enzyme immunoassay (EIA) for human cytosolic aspartate aminotransferase (c-AST) has been developed. Serum was incubated with anti-c-AST antibody-coated polystyrene beads, and further incubated with anti-c-AST antibody-peroxidase conjugate. The peroxidase activity bound to the polystyrene bead was proportional to the amount of c-AST. The method allows measurement of serum c-AST ranging from 50-2,000 micrograms/l. No cross-reactivity with m-AST or other serum components was observed. Recovery, within-day precision, and day-to-day precision were good. The levels of c-AST obtained by the proposed EIA were compared with those based on enzyme activity. The results suggest that there is a considerable excess of immunologically active but catalytically inactive c-AST in normal and patient's sera, and that variable specific activities of c-AST are may be found in sera from different individuals.
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PMID:Enzyme immunoassay of human cytosolic aspartate aminotransferase. 639 41

The rabbit antiserum and mouse monoclonal hybridoma antibody against porcine cytosolic aspartate aminotransferase (c-AAT) (or cytosolic glutamic oxaloacetic transaminase (c-GOT)) were produced and compared for the localization of c-AAT in rat liver. An indirect immunocytochemical technique was performed using peroxidase-conjugated goat immunoglobulin (Ig) G anti-rabbit IgG and peroxidase-conjugated rabbit IgG anti-mouse IgG as the second antibody. Rats were perfused with paraformaldehyde-lysine-periodate fixative and the liver fragments were immersed in 4% paraformaldehyde and transferred to 10% dimethyl sulfoxide overnight and subjected to cryostat sectioning. The rabbit IgG antibody, 3 individual monoclonal antibodies, and a mixture of these 3 monoclonal antibodies were applied to the tissue sections, respectively, using the same concentration. Under the same experimental conditions, the c-AAT was localized in each individual hepatocyte by both monoclonal and polyclonal antibodies. However, a mixture of three monoclonal antibodies gave stronger staining than a single monoclonal antibody; although two antibodies yield more intense staining than just one, it was still less intense than for three. The conventional rabbit polyclonal antibody against c-AAT produced more reaction product than the combined three monoclonal antibodies. It is concluded that for immunocytochemical study, the use of a single monoclonal antibody is sensitive enough to localize its tissue antigen under the present experimental condition. To obtain a stronger reaction product, a combination of several monoclonal antibodies, at least three or more, may give better staining.
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PMID:A comparative study of polyclonal and monoclonal antibodies for immunocytochemical localization of cytosolic aspartate aminotransferase in rat liver. 685 5

There is substantial evidence supporting the role of aspartate or glutamate as the neurotransmitter of the auditory nerve. The concentration of aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1), an enzyme associated with the metabolism of these amino acids, is high in axons and terminals of the auditory nerve. Antibodies were raised against aspartate aminotransferase and used in immunocytochemical studies to determine its localization in the cochlear nucleus of the guinea pig. Indirect immunofluorescence techniques were used for light microscopic localization of aspartate aminotransferase-like immunoreactivity in normal guinea pigs and guinea pigs with auditory nerve lesions. Fluorescent rings of aspartate aminotransferase-like immunoreactivity were seen around spherical cells in the anteroventral cochlear nucleus. In animals with auditory nerve lesions, rings were no longer seen in the ipsilateral cochlear nucleus. Immunoreactivity was also seen on cells in the posteroventral cochlear nucleus and in auditory nerve fibers. Ultrastructural studies were done in the rostral anteroventral cochlear nucleus, using the peroxidase-antiperoxidase technique. Aspartate aminotransferase-like immunoreactivity was seen at axosomatic synapses on large spherical cells in terminals with the morphological characteristics of auditory nerve terminals. Other classes of terminals on the soma of large spherical cells showed no immunoreactivity. It was concluded that aspartate aminotransferase-like immunoreactivity is present in axons and terminals of the auditory nerve. These findings indicate that aspartate aminotransferase-like immunoreactivity may serve as a marker at terminals where aspartate or glutamate is a neurotransmitter.
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PMID:Immunocytochemical localization of aspartate aminotransferase immunoreactivity in cochlear nucleus of the guinea pig. 694 43

A biochemical system was devised to identify aneuploids of Nicotiana tabacum. Leaf tissue from 6 nullihaploids, 4 nullisomics, and 10 monosomics was analyzed electrophoretically on slab acrylamide gels. The staining systems used were for peroxidase, esterase, superoxide dismutase, malate dehydrogenase, and glutamate oxaloacetate transaminase. Nullihaploids and nullisomics could be distinguished from each other and from haploid or disomic types by their unique isozyme banding patterns. The banding patterns of the monosomics closely resembled those of the disomic. Morphologically similar aneuploids from different populations had similar isozyme banding patterns.
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PMID:Identification of aneuploids in Nicotiana tabacum by isozyme banding patterns. 711 87

We investigated whether bile salts (BS) with different hydrophobic-hydrophilic properties interact with ethanol on bile secretion, enzyme (aspartate transaminase [AST], lactate dehydrogenase [LDH]) release in the perfusate, liver ultrastructure, and vesicular exocytosis in the isolated perfused rat liver. Ethanol (0.1 or 1%) promoted a rapid decrease of bile flow and BS secretion in livers perfused with taurocholate (TCA), the physiologic BS in the rat (-28% decrease of baseline values with 0.1% and -34% with 1% ethanol). The inhibitory effect of ethanol on bile flow and BS secretion was significantly (P < .02) attenuated by perfusing liver with the hydrophilic BS, tauroursodeoxycholate (TUDCA), and it was exacerbated (P < .02) by perfusion with the hydrophobic BS, taurodeoxycholate (TDCA). The release of AST and LDH in the perfusate was unaffected by 0.1% ethanol, but increased threefold to fivefold by 1% ethanol in TCA-perfused livers. This cytolitic effect of ethanol was not observed in TUDCA-perfused livers, but it was enhanced (P < .03) by perfusion with TDCA. No ultrastructural abnormalities were found in either TCA- or TUDCA-perfused livers, with or without 1% ethanol. Only minimal changes were found in livers perfused with TDCA alone, but, in the presence of TDCA, 1% ethanol induces marked mitochondrial damage. The biliary excretion of the fluid phase marker horseradish peroxidase was inhibited by ethanol, an effect reversed by TUDCA (P < .02) and exacerbated by TDCA (P < .04). In conclusion, this study demonstrates that hydrophilic BS such as TUDCA counteract the inhibitory effect of ethanol on bile secretion and vesicular exocytosis as well as the ethanol-induced cytolitic effect in the isolated perfused rat liver. In the presence of hydrophobic BS such as TDCA, the exposure to ethanol promotes a marked inhibition of bile secretion and vesicular exocytosis as well as prominent mitochondrial damage.
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PMID:Functional and ultrastructural features of ethanol/bile salts interaction in the isolated perfused rat liver. 770 87


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