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:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biotin deficiency in Aspergillus nidulans resulted in a 70% increase of the protein content and increased levels of free and bound aspartate, glutamate, serine, leucine and methionine. Likewise, the activities of NADP+ glutamate dehydrogenase, NAD+ gluatmate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were significantly increased. The total RNA content increased while the DNA content was unaffected. The rRNA/tRNA ratio remained higher in biotin-deficient cells. Supplementation of glutamate, aspartate, serine, leucine and methionine to the culture medium raised the rRNA/tRNA ratio, and the difference observed in the qualitative and the quantitative patterns of protein and dry cell mass between normal and biotin-deficient cultures was abolished.
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PMID:Factors affecting protein synthesis during biotin deficiency in Aspergillus nidulans. 4 77

Amino acid sequence and composition data of Escherichia coli dnaG primase protein and its tryptic peptides have confirmed that the dnaG gene contains an unusually high number of codons that are not frequently used in most E. coli genes. In 25 E. coli proteins analyzed the codons AUA, UCG, CCU, CCC, ACG, CAA, AAT, and AGG are infrequently used, occurring as 4% of the total codons in the reading frame and 11% and 10% in the nonreading frames. In dnaG they occur as 11% in the reading frame and 12% in the nonreading frames. The rpsU and rpoD genes, which flank the dnaG gene [Smiley, B. L., Lupski, J. R., Svec, P. S., McMacken, R. & Godson, G. N. (1982) Proc. Natl. Acad. Sci. USA 79, 4550-4554], however, have normal codon usage. Translational modulation using isoaccepting tRNA availability may therefore be part of the mechanism of keeping the dnaG gene expression low, while expression of the adjacent rpsU and rpoD genes on the same mRNA transcript is high.
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PMID:Evidence for use of rare codons in the dnaG gene and other regulatory genes of Escherichia coli. 633 95

RNA, DNA, total protein, transketolase (TK), alanine aminotransferase (AlAT), aspartate aminotransferase (AsAT), methionyl-tRNA (met-tRNA)- and cysteinyl-tRNA (cys-tRNA)-synthetases in the thymus and spleen of 46 intact rats exposed to hypokinesia and vitamin B1 deficiency were measured. It was found that 15-day hypokinesia induced a significant decrease of the thymus and spleen weight and an increase of AlAT in the thymus. Vitamin B1 deficiency (hydroxy thiamine in drinking water at a dose of 2 mg/kg body weight for 15 days) led to a substantial decrease of TK in blood, AlAT and AsAT in the spleen; it diminished AsAT and increased AlAT in the thymus. Combined exposure to hypokinesia and vitamin B1 deficiency caused a more marked decrease of the weight of lymph organs, a significant loss of body weight, an increase of DNA in the thymus and spleen, and an increase of TK, met-tRNA-synthetase and AlAT in the thymus. These results suggest that vitamin B1 deficiency aggravates disorders in protein and nucleic acid metabolism in the lymph organs of hypokinetic animals.
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PMID:[Several indicators of protein and nucleic acid metabolism in lymphoid organs of rats exposed to hypokinesia and vitamin B1 deficiency]. 857 40

A nuclear tRNA(Lys) gene from Arabidopsis thaliana was cloned and mutated so as to express tRNAs with altered anticodons which bind to a UAG nonsense (amber) codon and to the Arg (AGG), Asn (AAC,AAT), Gln (CAG) or Glu (GAG) codons. Concomitantly, a codon in the firefly luciferase gene for a functionally important Lys was altered to an amber codon, or to Arg, Asn, Gln, Glu, Thr and Trp codons, so as to construct reporter genes reliant upon incorporation of Lys. The altered tRNA(Lys) and luciferase genes were introduced into Nicotiana benthamiana protoplasts and expression of the mutated tRNAs was verified by translational suppression of the mutant firefly luciferase genes. Expression of the amber suppressor tRNA(LysCUA) from non-replicative vectors promoted 10-40% suppression of the luciferase nonsense reporters while expression of the amber and missense tRNA(Lys) suppressor genes from a geminivirus vector capable of replication promoted 30-80% suppression of the luciferase nonsense reporter and up to 10% suppression of the luciferase missense reporters with Arg, Asn, Gln and Glu codons.
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PMID:Nonsense and missense translational suppression in plant cells mediated by tRNA(Lys). 948 71

GTP hydrolysis by elongation factor Tu (EF-Tu) on the ribosome is induced by codon recognition. The mechanism by which a signal is transmitted from the site of codon-anticodon interaction in the decoding center of the 30S ribosomal subunit to the site of EF-Tu binding on the 50S subunit is not known. Here we examine the role of the tRNA in this process. We have used two RNA fragments, one which contains the anticodon and D hairpin domains (ACD oligomer) derived from tRNA(Phe) and the second which comprises the acceptor stem and T hairpin domains derived from tRNA(Ala) (AST oligomer) that aminoacylates with alanine and forms a ternary complex with EF-Tu. GTP. While the ACD oligomer and the ternary complex containing the Ala-AST oligomer interact with the 30S and 50S A site, respectively, no rapid GTP hydrolysis was observed when both were bound simultaneously. The presence of paromomycin, an aminoglycoside antibiotic that binds to the decoding site and stabilizes codon-anticodon interaction in unfavorable coding situations, did not increase the rate of GTP hydrolysis. These results suggest that codon recognition as such is not sufficient for GTPase activation and that an intact tRNA molecule is required for transmitting the signal created by codon recognition to EF-Tu.
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PMID:Intact aminoacyl-tRNA is required to trigger GTP hydrolysis by elongation factor Tu on the ribosome. 1067 22

A 40-year-old Chinese-American woman with breast carcinoma metastatic to her lungs presented with a 3-month history of erosions on her inner thighs (Figure 1) and medial left shoulder. Faint livedo reticularis was evident on her legs as well. She had difficulty in walking and raising her shoulders. Her cutaneous examination was also notable for cuticular erythema (Figure 2) and mild periorbital erythema and edema. She had no systemic or rheumatologic complaints other than some difficulty in swallowing. Her blood chemistry values were notable for a creatinine kinase of 564 IU/L (5-200 IU/L), alanine aminotransferase 161 U/L (0-40 U/L) and aspartate aminotransferase 93 U/L (0-40 U/L), and an antinuclear antibody titer of 1:2560. Other blood chemistries and antibody serologies (anti-Jo-1, anti-Mi-2 and other anti-tRNA synthetase, anti-Ro/SSA, anti-U1RNP, anti-PM/Scl, and anti-Ku) were within normal limits. A biopsy specimen was obtained from an area of intact skin close to a right thigh ulceration that showed subtle vacuolar alteration at the dermo-epidermal junction with occasional necrotic keratinocyte (Figure 3). Melanophages and telangiectases were present. Within the subcutis there was fibrin deposition and neutrophils. A diagnosis of dermatomyositis was made. The patient received oral prednisone 20 mg three times a day, and her ulcerations resolved. Her creatinine kinase, alanine aminotransferase, and aspartate aminotransferase values returned to normal over the course of 3 weeks, but her antinuclear antibody was unchanged. Radiographic studies concurrently noted that her breast cancer had recurred in her lungs; plans were made to treat her with chemotherapy. The patient was lost to close follow-up, but it was learned that her erosions had reoccurred while her prednisone was tapered and resolved when her dosage of prednisone was increased.
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PMID:Ulcerative paraneoplastic dermatomyositis secondary to metastatic breast cancer. 1660 44

Methanococcus maripaludis and Methanocaldococcus jannaschii produce cysteine for protein synthesis using a tRNA-dependent pathway. These methanogens charge tRNA(Cys) with l-phosphoserine, which is also an intermediate in the predicted pathways for serine and cystathionine biosynthesis. To establish the mode of phosphoserine production in Methanococcales, cell extracts of M. maripaludis were shown to have phosphoglycerate dehydrogenase and phosphoserine aminotransferase activities. The heterologously expressed and purified phosphoglycerate dehydrogenase from M. maripaludis had enzymological properties similar to those of its bacterial homologs but was poorly inhibited by serine. While bacterial enzymes are inhibited by micromolar concentrations of serine bound to an allosteric site, the low sensitivity of the archaeal protein to serine is consistent with phosphoserine's position as a branch point in several pathways. A broad-specificity class V aspartate aminotransferase from M. jannaschii converted the phosphohydroxypyruvate product to phosphoserine. This enzyme catalyzed the transamination of aspartate, glutamate, phosphoserine, alanine, and cysteate. The M. maripaludis homolog complemented a serC mutation in the Escherichia coli phosphoserine aminotransferase. All methanogenic archaea apparently share this pathway, providing sufficient phosphoserine for the tRNA-dependent cysteine biosynthetic pathway.
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PMID:Biosynthesis of phosphoserine in the Methanococcales. 1707 63

Drug-induced liver injury (DILI) is the primary adverse event that results in the withdrawal of drugs from the market and a frequent reason for the failure of drug candidates in the pre-clinical or clinical phases of drug development. This paper presents an approach for identifying potential liver toxicity genomic biomarkers from a liver toxicity biomarker study involving the paired compounds entacapone ("non-liver toxic drug") and tolcapone ("hepatotoxic drug"). Molecular analysis of the rat liver and plasma samples, combined with statistical analysis, revealed many similarities and differences between the in vivo biochemical effects of the two drugs. Six hundred and ninety-five genes and 61 pathways were selected based on the classification scheme. Of the 61 pathways, 5 were specific to treatment with tolcapone. Two of the 12 animals in the tolcapone group were found to have high ALT, AST, or TBIL levels. The gene Vars2 (valyl-tRNA synthetase 2) was identified in both animals and the pathway to which it belongs, the aminoacyl-tRNA biosynthesis pathway, was one of the three most significant tolcapone-specific pathways identified.
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PMID:Identification and categorization of liver toxicity markers induced by a related pair of drugs. 2184 99

The first complete mitochondrial genome (27,943 bp) of the halymenialean red alga, Grateloupia angusta, was sequenced. The circular mitogenome contains 47 genes, including 26 protein-coding, 19 tRNA and 2 rRNA genes. The rps3 and rpl16 genes are overlapped by 7 bp. The majority of protein-coding genes (17 of 26 genes) use typical ATG start codon, however, 9 genes use alternative start codons such as ATT, AAT, TTA and TTG. The G. angusta mitogenome shows a significant difference to that of Chondrus crispus (Gigartinales) in gene synteny and tRNA compositions.
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PMID:Complete mitochondrial genome of the marine red alga Grateloupia angusta (Halymeniales). 2378 73

The complete 15,223-bp mitochondrial genome (mitogenome) of Tryporyza incertulas (Walker) (Lepidoptera: Pyraloidea: Crambidae) was determined, characterized and compared with seven other species of superfamily Pyraloidea. The order of 37 genes was typical of insect mitochondrial DNA sequences described to date. Compared with other moths of Pyraloidea, the A+T biased (77.0%) of T. incertulas was the lowest. Eleven protein-coding genes (PCGs) utilized the standard ATN, but cox1 used CGA and nad4 used AAT as the initiation codons. Ten protein-coding genes had the common stop codon TAA, except nad3 having TAG as the stop codon, and cox2, nad4 using T, TA as the incomplete stop codons, respectively. All of the tRNA genes had typical cloverleaf secondary structures except trnS1(AGN), in which the dihydrouridine (DHU) arm did not form a stable stem-loop structure. There was a spacer between trnQ and nad2, which was common in Lepidoptera moths. A 6-bp motif 'ATACTA' between trnS2(UCN) and nad1, a 7-bp motif "AGC(T)CTTA" between trnW and trnC and a 6-bp motif "ATGATA" of overlapping region between atp8 and atp6 were found in Pyraloidea moths. The A+T-rich region contained an 'ATAGT(A)'-like motif followed by a poly-T stretch. In addition, two potential stem-loop structures, a duplicated 19-bp repeat element, and two microsatellites '(TA)12' and '(TA)9' were observed in the A+T-rich region of T. incertulas mitogenome. Finally, the phylogenetic relationships of Pyraloidea species were constructed based on amino acid sequences of 13 PCGs of mitogenomes using Bayesian inference (BI) and maximum likelihood (ML) methods. These molecular-based phylogenies supported the morphological classification on relationships within Pyraloidea species.
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PMID:Characterization of the complete mitochondrial genome of Tryporyza incertulas, in comparison with seven other Pyraloidea moths. 2395 73


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