Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.6.1.2 (alanine aminotransferase)
26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete amino acid sequence of human liver cytosolic alanine aminotransferase (GPT) (EC 2.6.1.2) is presented. Two primary sets of overlapping fragments were obtained by cleavage of the pyridylethylated protein at methionyl and lysyl bonds with cyanogen bromide and Achromobacter protease I, respectively. Isolated peptides were analyzed with a protein sequencer or with a plasma desorption time of flight mass spectrometer and placed in the sequence on the basis of their molecular mass and homology to the sequence of rat GPT. The protein was found to be acetylated at the amino terminus and contained 495 amino acid residues. The Mr of the subunit was calculated to be 54,479, which was in good agreement with a Mr of 55,000 estimated by SDS-PAGE, and also indicated that the active enzyme with a Mr of 114,000 was a homodimer composed of two identical subunits. The amino acid sequence is highly homologous to that of rat GPT (87.9% identity) recently determined [Ishiguro, M., Suzuki, M., Takio, K., Matsuzawa, T., & Titani, K. (1991) Biochemistry 30, 6048-6053]. All of the crucial amino acid residues are conserved in human GPT, which seem to be hydrogen bonding to pyridoxal 5'-phosphate in rat GPT by the sequence homology to other alpha-aminotransferases with known tertiary structures.
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PMID:Complete amino acid sequence of human liver cytosolic alanine aminotransferase (GPT) determined by a combination of conventional and mass spectral methods. 193 70

The complete amino acid sequence of rat liver cytosolic alanine aminotransferase (EC 2.6.1.2) is presented. Two primary sets of overlapping fragments were obtained by cleavage of the pyridylethylated protein at methionyl and lysyl bonds with cyanogen bromide and Achromobacter protease I, respectively. The protein was found to be acetylated at the amino terminus and contained 495 amino acid residues. The molecular weight of the subunit was calculated to be 55,018 which was in good agreement with a molecular weight of 55,000 determined by SDS-PAGE and also indicated that the active enzyme with a molecular weight of 114,000 was a homodimer composed of two identical subunits. No highly homologous sequence was found in protein sequence databases except for a 20-residue sequence around the pyridoxal 5'-phosphate binding site of the pig heart enzyme [Tanase, S., Kojima, H., & Morino, Y. (1979) Biochemistry 18, 3002-3007], which was almost identical with that of residues 303-322 of the rat liver enzyme. In spite of rather low homology scores, rat alanine aminotransferase is clearly homologous to those of other aminotransferases from the same species, e.g., cytosolic tyrosine aminotransferase (24.7% identity), cytosolic aspartate aminotransferase (17.0%), and mitochondrial aspartate aminotransferase (16.0%). Most of the crucial amino acid residues hydrogen-bonding to pyridoxal 5'-phosphate identified in aspartate aminotransferase by X-ray crystallography are conserved in alanine aminotransferase. This suggests that the topology of secondary structures characteristic in the large domain of other alpha-aminotransferases with known tertiary structure may also be conserved in alanine aminotransferase.
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PMID:Complete amino acid sequence of rat liver cytosolic alanine aminotransferase. 204 42

Two IgG1 type monoclonal antibodies ALT-01 and ALT-04 were prepared by two different immunization schedules. ALT-01 was generated by fusing murine myeloma NS-1 cells with splenocytes from a BALB/c mouse immunized by human lung squamous carcinoma cells, which were coated by antisera to mixed human lymphocytes. For preparation of ALT-04, human lung squamous carcinoma xenograft-bearing nude mice were injected I. P. with the spleen cells of normal BALB/c mice in order to acquire immunofunction. The spleen cells from these tumor-bearing nude mice were fused with NS-1 cells. Then, these hybridomas were screened and cloned for 3 times. Two antibodies were shown to recognize the surface antigen on human lung carcinoma cells and several kinds of tumor cell lines but not those on normal cell lines. ALT-01 reacted to neither human lung carcinoma tissue nor its xenograft. ALT-04 reacted to human lung carcinoma tissue, of which, reaction to adenocarcinoma was the strongest but not to various normal tissues. Immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis and autoradiography was used to detect the associated antigen in 35S-labeled human lung carcinoma cells. Antigens, reacting to ALT-01, show one band of Mr 38,000 but those to ALT-04 reveal two bands of Mr 48,000 and 36,000.
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PMID:[Reactivity of monoclonal antibodies ALT-01 and ALT-04 and identification of lung cancer-associated antigens]. 344 54

It has been reported that in a long-term feeding study 12,000 ppm of di(2-ethylhexyl)phthalate (DEHP) in the diet produced hepatocellular carcinomas in male and female F-344 rats while 6000 ppm DEHP produced the same tumor type in male and female B6C3F1 mice. In terms of the actual numbers of animals with tumors DEHP produced a greater response in mice than rats. DEHP and its principal hydrolysis product, mono(2-ethylhexyl)phtalate (MEHP) produce multiple effects in the animal such as liver peroxisomal proliferation and hyperplasia. Accordingly, genotoxicity as DNA repair or unscheduled DNA synthesis (UDS) and cell replication as the percentage of cells undergoing scheduled DNA synthesis (SDS or S phase) were determined in mouse hepatocytes in vitro and in vivo in response to DEHP and MEHP. UDS and SDS were determined by autoradiographic quantitation of [3H]-thymidine incorporation in primary hepatocyte cultures treated directly or isolated from B6C3F1 male mice treated in vivo. No DNA repair was observed in mouse hepatocyte cultures treated with up to 1.0 mM DEHP or 0.5 mM MEHP. No DNA repair was observed in cultures from mice treated with up to 500 mg/kg DEHP 12, 24 or 48 h previously or from animals treated up to 28 days with 6000 ppm DEHP in the diet. At 24 h following treatment with 500 mg/kg DEHP, 3.1% of the hepatocytes were in S phase compared to control values of 0.2%. Administration of DEHP in the diet at 6000 ppm produced 9.2% of the cells in S phase at day 7 with the value returning to control levels by day 14. On day 28 of the feeding study the liver to body weight ratios had almost doubled in the group treated with DEHP compared to controls. No increase in the liver-specific enzyme alanine aminotransferase was seen in the serum following treatment with 500 mg/kg DEHP, indicating that the hyperplasia was due to mitogenic stimulation rather than regenerative hyperplasia in response to cytotoxicity. Increases in the endpoints relating to hyperplasia in response to DEHP were greater in the mouse than those that have been reported in the rat. Thus, the carcinogenic response of DEHP correlates better with induced hyperplasia rather than with genotoxicity.
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PMID:Correlation of the carcinogenic potential of di(2-ethylhexyl)phthalate (DEHP) with induced hyperplasia rather than with genotoxic activity. 357 34

beta-Alanine aminotransferase from rabbit liver has been purified 1,700-fold over the initial liver extract. The purified enzyme was shown to be homogeneous by disc electrophoresis and SDS polyacrylamide electrophoresis. The molecular weight of the purified enzyme determined by gel filtration was 95,000 +/- 5,700 and the subunit molecular weight was 48,000 +/- 2,100. The enzyme showed absorption maxima at 282, 330, and 414 nm and contained only 1 mol of pyridoxal 5'-phosphate/mol of dimer. The pH optimum for enzyme activity was 8.8 and the Km values for beta-alanine and 2-oxoglutaric acid were calculated to be 3.9 and 1.4 mM, respectively. The enzyme catalyzed transamination of various omega-amino acids with 2-oxoglutaric acid, which was a favourable amino acceptor. beta-Alanine, gamma-aminobutyric acid, and beta-aminoisobutyric acid, which are naturally occurring substrates, were preferred amino donors, but taurine, alanine, ornithine, spermine, and spermidine were not. 6-Azauracil inhibited the enzyme activity with a Ki of approximately 1.5 mM. From the above properties, beta-alanine aminotransferase from rabbit liver was seen to closely resemble with 4-aminobutyrate aminotransferase from liver and brain.
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PMID:Purification and properties of beta-alanine aminotransferase from rabbit liver. 681 89

Tyrosine aminotransferase was purified to homogeneity from epimastigotes of Trypanosoma cruzi by a method involving chromatography on DEAE-cellulose, gel filtration on Sephacryl S-200 and chromatography on Mono Q in an f.p.l.c. system. The purified enzyme showed a single band in SDS/PAGE, with an apparent molecular mass of 45 kDa. Since the apparent molecular mass of the native enzyme, determined by gel filtration, is 91 kDa, the native enzyme is a dimer of similar subunits. The amino-acid composition was determined, as well as the sequences of three internal peptides obtained by CNBr cleavage at Met residues. Both criteria suggest considerable similarity with the tyrosine aminotransferases from rat and from human liver. The enzyme contains nine 1/2 Cys residues, three free and the others forming three disulphide bridges. The enzyme is not N-glycosylated. The isoelectric point is 4.6-4.8. The optimal pH for the reaction of the enzyme with tyrosine as a substrate is 7.0. The apparent Km values for tyrosine, phenylalanine and tryptophan, with pyruvate as a co-substrate, were 6.8, 17.9 and 21.4 mM, respectively, whereas those for pyruvate, alpha-oxoglutarate and oxaloacetate, with tyrosine as a substrate, were 0.5, 38 and 16 mM respectively. The purified tyrosine aminotransferase acts as an alanine aminotransferase as well and the activity seems to reside in the same enzyme molecule. The results suggest that the enzyme is a general aromatic-amino-acid transaminase, with high sequence similarity to tyrosine aminotransferases from rat and human liver.
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PMID:Purification and partial structural and kinetic characterization of tyrosine aminotransferase from epimastigotes of Trypanosoma cruzi. 810 Apr 16

Stress exhibits adverse effects on many vital processes in which glycoproteins play a significant role(e.g. cell-cell/matrix interactions, immune response, neoplastic growth, implantation, prenatal development), yet only scarce attention has been directed towards studying stress induced changes in glycoprotein patterns. Using SDS-electrophoresis, blotting and digoxigenin-labelled lectins (Sambucus nigra agglutinin, Galanthus nivalis agglutinin, Datura stramonium agglutinin, Maackia amurensis agglutinin and peanut (Arachis hypogaea) agglutinin),sera were analysed from 30 individuals chosen randomly from a severely stressed population of 309 male volunteers with no specific medical symptoms. Significant changes were found in glycoprotein pattern and content, compared with healthy controls of matching age and sex. Occasionally minor non-specific deviations from the reference values for several analytes (haemoglobin, glucose, bilirubin and alanine aminotransferase) were detected in the tested group, but glycoprotein GP4S (Mr = 45 000), detected by Datura stramonium agglutinin and Sambucus nigra agglutinin, appeared in 96.7% of samples of the stressed population. The same population also revealed an approximately 500-fold increase of GP37 in comparison with the control sera. These results suggest that stress, as a non-specific syndrome, induces specific biochemical changes, which could be of diagnostic relevance as risk makers before any more serious symptoms of stress-related consequences have developed.
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PMID:Changes of glycoprotein patterns in sera of humans under stress. 883 40

To identify pretransplant factors that are influencing survival after orthotopic liver transplantation a Cox proportional hazards regression model was applied to 118 children with chronic terminal liver failure transplanted at Medical School Hannover during the period of 1978 to 1994. The response variable was survival, as covariates a total of 19 pretransplant variables were entered--i.e. age, diagnosis (biliary cirrhosis, metabolic cirrhosis, postnecrotic cirrhosis, cryptogenetic cirrhosis) sex, laparotomy prior to OLT, height, weight, standard deviation scores for height and weight, date of first OLT, serum alanine aminotransferase, asparagine aminotransferase, albumin, total bilirubin, cholinesterase activity, glomerular filtration rate, and prothrombin time. Significant independent predictors of survival after OLT were bilirubin (P=0.0024), SDS for weight (P=0.034), and albumin (P=0.039). In a subsequent discriminant analysis cut off points for these variables could be identified--i.e., bilirubin >340 micromol/L, SDS for weight <-2.2 and albumin < 33 g/L. Patients with one or more of these risk factors were grouped as urgent indication group (n=76) and those with no risk factor as elective indication group (n=42). Comparing the posttransplantation survival in these groups there is a statistically significant difference at 1 year (57% vs. 90.5%) and 4 years (49% vs. 90.5%) after OLT (P=0.0001, log rank test). It is concluded that the risk of OLT is much higher if liver function is very poor. Optimal nutritional support prior to transplantation is mandatory to optimise the clinical status of the children and to improve the results of OLT.
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PMID:Liver transplantation in children with chronic end stage liver disease: factors influencing survival after transplantation. 890 Mar 4

Cytosolic alanine aminotransferase (c-AAT) was purified up to 203- and 120-fold, from the liver of two freshwater teleosts Clarias batrachus (air-breathing, carnivorous) and Labeo rohita (water-breathing, herbivorous), respectively. The enzyme from both fish showed similar elution profiles on a DEAE-Sephacel ion exchange column. SDS-PAGE of purified enzymes revealed two subunits of 54 and 56 kDa, in both fish. The apparent Km values for l-alanine were 18.5+/-0.48 and 23.55+/-0.60 mM, whereas for 2-oxoglutarate the Km values were observed to be 0.29+/-0.023 and 0.33+/-0.028 mM for the enzyme from C. batrachus and L. rohita, respectively. With l-alanine as substrate, aminooxyacetic acid was found to act as a competitive inhibitor with KI values of 6.4 x 10(-4) and 3.4 x 10(-4) mM with c-AAT of C. batrachus and L. rohita, respectively. However, when 2-oxoglutarate was used as substrate, aminooxyacetic acid showed uncompetitive inhibition with similar KI values for purified c-AAT from both fish. Temperature and pH profiles of the enzyme did not show any marked differences between the two fish examined. These results suggest that liver c-AAT, isolated from these two fish species adapted to different modes of life, remain unaltered structurally. However, at the kinetic level, liver c-AAT from C. batrachus exhibits significantly higher affinity for the substrate l-alanine and decreased affinity for its metabolic inhibitor, in comparison to that of the enzyme purified from L. rohita. Such functional changes seem to be of physiological significance and also provide preliminary evidence for subtle changes in the enzyme as a mark of metabolic adaptation in the fish to different physiological demands.
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PMID:Purification and properties of cytosolic alanine aminotransferase from the liver of two freshwater fish, Clarias batrachus and Labeo rohita. 1499 Feb 16

To find out the active principles against ethanol-induced toxicity in mice, Andrographis paniculata Nees. (Ap) was chosen and isolated andrographolide (ANDRO) and arabinogalactan proteins (AGPs). ANDRO was detected by HPTLC, FTIR and quantified by HPLC (10mg/g of Ap powder). AGPs was detected by beta-glucosyl Yariv staining of SDS-PAGE gel, FTIR and quantified by single radial gel diffusion assay with beta-glucosyl Yariv reagent (0.5mg/g Ap powder). The mice are pretreated intra-peritoneally (i.p.) with different doses (62.5, 125, 250, and 500mg/kg) of body weight of mice] of ANDRO and AGPs for 7 days and then ethanol (7.5g/kg of body weight) was injected, i.p. Besides, silymarin was used as standard hepatoprotective agent for comparative study with ANDRO and AGPs. The ameliorative activity of ANDRO and AGP against hepatic renal alcohol toxicity was measured by assessing GOT, GPT, ACP, ALP and LP levels in liver and kidney. It has been observed that pretreatment of mice with ANDRO and AGPs at 500mg/kg of body weight and 125mg/kg of body weight respectively could able to minimize the toxicity in compare to ethanol treated group as revealed by the different enzymatic assay in liver and kidney tissues and the results were comparable with silymarin. Hence, out of several ill-defined compounds present in Ap, ANDRO and AGPs are the potential bioactive compounds responsible for protection against ethanol-induced toxicity.
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PMID:Protective activity of andrographolide and arabinogalactan proteins from Andrographis paniculata Nees. against ethanol-induced toxicity in mice. 1712 22


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