scholarly journals Characteristics of hepatic alanine-glyoxylate aminotransferase in different mammalian species

1978 ◽  
Vol 169 (1) ◽  
pp. 113-122 ◽  
Author(s):  
T Noguchi ◽  
E Okuno ◽  
Y Takada ◽  
Y Minatogawa ◽  
K Okai ◽  
...  
Keyword(s):  
Amino Acids ◽  
Substrate Specificity ◽  
Physical Properties ◽  
Mouse Liver ◽  
Mammalian Species ◽  
The Other ◽  
Enzyme Preparations ◽  
Amino Donor ◽  
Glyoxylate Aminotransferase

Mitochondrial extracts of dog, cat, rat and mouse liver contain two forms of alanine-glyoxylate aminotransferase (EC 2.6.1.44): one, designated isoenzyme 1, has mol.wt. approx. 80 000 and predominates in dog and cat liver; the other, designated isoenzyme 2, has mol.wt. approx. 175 000 and predominates in rat and mouse liver. In rat and mouse liver, isoenzyme 1 activity was increased by the injection in vivo of glucagon, but not isoenzyme 2 activity. Isoenzyme 1 was purified and characterized from liver mitochondrial extracts of the four species. Both rat and mouse enzyme preparations catalysed transamination between a number of L-amino acids and glyoxylate, and with L-alanine as amino donor the effective amino acceptors were glyoxylate, phenylpyruvate and hydroxypyruvate. In contrast, both dog and cat enzyme preparations were specific for L-alanine and L-serine with glyoxylate, and used glyoxylate and hydroxypyruvate as effective amino acceptors with L-alanine. Evidence that isoenzyme 1 is identical with serine-pyruvate aminotransferase (EC 2.6.1.51) was obtained. Isoenzyme 2 was partially purified from mitochondrial extracts of rat and mouse liver. Both enzyme preparations were specific for L-alanine and glyoxylate. On the basis of physical properties and substrate specificity, it was concluded that isoenzyme 2 is a separate enzyme. Some other properties of isoenzymes 1 and 2 are described.

scholarly journals Histone Adduction with Nicotine: A Bio-Ams Study

Radiocarbon ◽  
1997 ◽  
Vol 39 (3) ◽  
pp. 293-297 ◽  
Author(s):  
X. H. Wu ◽  
H. F. Wang ◽  
Y. F. Liu ◽  
X. Y. Lu ◽  
J. J. Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Human Exposure ◽  
Mouse Liver ◽  
Dose Range ◽  
The Other ◽  
Histone 3 ◽  
Protein Adduction ◽  
Dna Adduction

Based on the study of DNA adduction with nicotine, we have measured the mouse hepatic histone adduction with 14C-labeled nicotine in vivo by bio-accelerator mass spectrometry (bio-AMS). In the exposure of mice to nicotine, the dose range administered was from 0.2 μg to 6.0 μg kg b.w.-1, which was equivalent to a very low level of human exposure to cigarette smoke. The adducts of either histone 1 (H1) or histone 3 (H3) with nicotine in mouse liver increased markedly with increasing nicotine dose. Our results have demonstrated that in the study of protein adduction with toxic xenobiotics as a biomarker, the AMS method achieves the highest sensitivity, 4.6 × 10-17 mol (46 amol) adducts per mg H1 protein, compared to all the other methods used previously.

scholarly journals Evolution of the C30 Carotenoid Synthase CrtM for Function in a C40 Pathway

2002 ◽  
Vol 184 (23) ◽  
pp. 6690-6699 ◽  
Author(s):  
Daisuke Umeno ◽  
Alexander V. Tobias ◽  
Frances H. Arnold
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Substrate Specificity ◽  
Significant Variation ◽  
The Other ◽  
Biosynthetic Pathways ◽  
Product Range

ABSTRACT The C30 carotene synthase CrtM from Staphylococcus aureus and the C40 carotene synthase CrtB from Erwinia uredovora were swapped into their respective foreign C40 and C30 biosynthetic pathways (heterologously expressed in Escherichia coli) and evaluated for function. Each displayed negligible ability to synthesize the natural carotenoid product of the other. After one round of mutagenesis and screening, we isolated 116 variants of CrtM able to synthesize C40 carotenoids. In contrast, we failed to find a single variant of CrtB with detectable C30 activity. Subsequent analysis revealed that the best CrtM mutants performed comparably to CrtB in an in vivo C40 pathway. These mutants showed significant variation in performance in their original C30 pathway, indicating the emergence of enzymes with broadened substrate specificity as well as those with shifted specificity. We discovered that Phe 26 alone determines the specificity of CrtM. The plasticity of CrtM with respect to its substrate and product range highlights the potential for creating further new carotenoid backbone structures.

scholarly journals Functional Analysis of All Aminotransferase Proteins Inferred from the Genome Sequence of Corynebacterium glutamicum

2005 ◽  
Vol 187 (22) ◽  
pp. 7639-7646 ◽  
Author(s):  
Jan Marienhagen ◽  
Nicole Kennerknecht ◽  
Hermann Sahm ◽  
Lothar Eggeling
Keyword(s):  
Corynebacterium Glutamicum ◽  
Branched Chain Amino Acids ◽  
The Other ◽  
Deletion Mutants ◽  
Cluster Assembly ◽  
Sulfur Transfer ◽  
Amino Donor ◽  
Putative Aminotransferase ◽  
Branched Chain

ABSTRACT Twenty putative aminotransferase (AT) proteins of Corynebacterium glutamicum, or rather pyridoxal-5′-phosphate (PLP)-dependent enzymes, were isolated and assayed among others with l-glutamate, l-aspartate, and l-alanine as amino donors and a number of 2-oxo-acids as amino acceptors. One outstanding AT identified is AlaT, which has a broad amino donor specificity utilizing (in the order of preference) l-glutamate > 2-aminobutyrate > l-aspartate with pyruvate as acceptor. Another AT is AvtA, which utilizes l-alanine to aminate 2-oxo-isovalerate, the l-valine precursor, and 2-oxo-butyrate. A second AT active with the l-valine precursor and that of the other two branched-chain amino acids, too, is IlvE, and both enzyme activities overlap partially in vivo, as demonstrated by the analysis of deletion mutants. Also identified was AroT, the aromatic AT, and this and IlvE were shown to have comparable activities with phenylpyruvate, thus demonstrating the relevance of both ATs for l-phenylalanine synthesis. We also assessed the activity of two PLP-containing cysteine desulfurases, supplying a persulfide intermediate. One of them is SufS, which assists in the sulfur transfer pathway for the Fe-S cluster assembly. Together with the identification of further ATs and the additional analysis of deletion mutants, this results in an overview of the ATs within an organism that may not have been achieved thus far.

Response of strains of Rhizobium on nodulation, grain yield, protein and amino acids content of chick pea (Cicer arietinum Linn.)

1979 ◽  
Vol 93 (1) ◽  
pp. 47-49 ◽  
Author(s):  
R. Rai ◽  
S. N. Singh
Keyword(s):  
Amino Acids ◽  
Grain Yield ◽  
Cicer Arietinum ◽  
Crude Protein ◽  
Dry Weight ◽  
The Other ◽  
Chick Pea ◽  
Alkali Soil ◽  
Nodulation Capacity

SummaryNine strains of Rhizobium sp. were studied in vivo for their nodulation capacity, leghaemoglobin content, grain yield, crude protein and 16 amino acids content, in the chick pea variety C 235 grown on a calcareous saline alkali soil. There was no significant correlation between grain yield and number of nodules (r = 0·37) or dry weight of nodules (r = 0·29), but grain yield was significantly correlated with leghaemoglobin content of nodules (r = 0·95). Of the 16 amino acids analysed in seed samples, aspartic, glutamic, proline and histidine were greatest with strain H 45; glycine, leucine and arginine with strain F 6; norleucine, tyrosine and phenylalanine with strain KG 38; and alanine and valine were greatest with strain KG 41. Strain KG 38 led to significantly higher grain yield than the other strains.

THYROID PROTEINS AND HORMONE SYNTHESIS IN VARIOUS BENIGN THYROID DISEASES: IN VIVO AND ORGAN CULTURE STUDIES

1973 ◽  
Vol 73 (1) ◽  
pp. 22-34 ◽  
Author(s):  
Colette Thomas-Morvan ◽  
Berthe M. Nataf ◽  
Maurice Tubiana
Keyword(s):  
Amino Acids ◽  
Organ Culture ◽  
Thyroid Tissue ◽  
The Other ◽  
Benign Diseases ◽  
Culture Studies ◽  
Hormone Synthesis ◽  
Thyroid Glands ◽  
Benign Thyroid

ABSTRACT The iodoproteins were extracted from 61 thyroid glands with signs of various benign diseases. In 59, the solubility properties and ultracentrifugation behaviour of the iodoproteins were normal, although the hormone synthesis was deficient. The incorporation of radioiodine into the hormones (T4* and T3) was smallest when the iodination of thyroglobulin (Tg) was lowest. In these cases the concentration of Tg was less than normal, but is seemed that the disorders of hormone synthesis were correlated with a deficiency in the iodination of Tg. Two goitres were clearly different from the other cases studied; thus anomalies of the iodoproteins are rare. In these two goitres, Tg was virtually absent, although thyroid hormones were synthesized. Electrophoresis on acrylamide gel in one of these goitres showed 3 protein bands corresponding to the light fractions in extracts of normal thyroid tissue. Albumin (F1) was the only iodinated protein of this goitre and seemed to support hormone synthesis. Albumin did not appear to be synthesized by the thyroid tissue since 14C-amino acids were not incorporated into this fraction in organ culture. The other fractions (F2 and F3) did not incorporate radioiodine but appeared to incorporate 14C-amino acids to a slight extent. It is possible that this goitre is able to synthesize the precursors of Tg but not Tg itself.

scholarly journals Specificity of human rhinovirus 2Apro is determined by combined spatial properties of four cleavage site residues

2013 ◽  
Vol 94 (7) ◽  
pp. 1535-1546 ◽  
Author(s):  
David Neubauer ◽  
Martina Aumayr ◽  
Irene Gösler ◽  
Tim Skern
Keyword(s):  
Amino Acids ◽  
Substrate Specificity ◽  
Cleavage Site ◽  
Antiviral Agents ◽  
Genetic Group ◽  
Human Rhinovirus ◽  
C Terminus ◽  
Group B

The 2A proteinase (2Apro) of human rhinoviruses cleaves the virally encoded polyprotein between the C terminus of VP1 and its own N terminus. Poor understanding of the 2Apro substrate specificity of this enzyme has hampered progress in developing inhibitors that may serve as antiviral agents. We show here that the 2Apro of human rhinovirus (HRV) 1A and 2 (rhinoviruses from genetic group A) cannot self-process at the HRV14 (a genetic group B rhinovirus) cleavage site. When the amino acids in the cleavage site of HRV2 2Apro (Ile-Ile-Thr-Thr-Ala*Gly-Pro-Ser-Asp) were singly or doubly replaced with the corresponding HRV14 residues (Asp-Ile-Lys-Ser-Tyr*Gly-Leu-Gly-Pro) at positions from P3 to P2′, HRV1A and HRV2 2Apro cleavage took place at WT levels. However, when three or more positions of the HRV1A or 2 2Apro were substituted (e.g. at P2, P1 and P2′), cleavage in vitro was essentially eliminated. Introduction of the full HRV14 cleavage site into a full-length clone of the HRV1A and transfection of HeLa cells with a transcribed RNA did not give rise to viable virus. In contrast, revertant viruses bearing cysteine at the P1 position or proline at P2′ were obtained when an RNA bearing the three inhibitory amino acids was transfected. Reversions in the enzyme affecting substrate specificity were not found in any of the in vivo experiments. Modelling of oligopeptide substrates onto the structure of HRV2 2Apro revealed no appreciable differences in residues of HRV2 and HRV14 in the respective substrate binding sites, suggesting that the overall shape of the substrate is important in determining binding efficiency.

scholarly journals Urinary excretion of isomers of biliverdin after destruction in vivo of haemoproteins and haemin

1985 ◽  
Vol 229 (2) ◽  
pp. 477-483 ◽  
Author(s):  
K Hirota ◽  
S Yamamoto ◽  
H A Itano
Keyword(s):  
Urinary Excretion ◽  
Mammalian Species ◽  
Fold Increase ◽  
The Other ◽  
Chemical Degradation ◽  
Isomeric Composition ◽  
Other Hand ◽  
Biliverdin Ix ◽  
Physiological Values

The amount and isomeric composition of urinary biliverdin in rabbits were analysed by h.p.l.c. Physiological values were maintained after the injection of haemin. On the other hand, when haemoglobins from several mammalian species were injected into rabbits, the excretion of biliverdin-IX alpha and biliverdin-IX beta were increased 6-18-fold and 32-66-fold respectively over physiological excretion. Injection of myoglobin resulted in a 44-fold increase in excretion of the IX alpha-isomer. Coupled oxidation with ascorbate of haemoglobin and myoglobin by oxygen produced mainly the IX alpha- and IX beta-isomers from haemoglobin and the IX alpha-isomer from myoglobin. The destruction of part of the haem from injected haemoproteins by non-enzymic chemical degradation would account for the observed respective increases in the excretion of biliverdin isomers. The excretion of biliverdin isomers after the injection of phenylhydrazine into rabbits was similar to that after the injection of haemoglobin.

scholarly journals Synthesis of ophthalmic acid in liver and kidney in vivo

1978 ◽  
Vol 170 (2) ◽  
pp. 415-419 ◽  
Author(s):  
M Orlowski ◽  
S Wilk
Keyword(s):  
Amino Acids ◽  
Mouse Liver ◽  
Significant Proportion ◽  
Rapid Synthesis ◽  
Gamma Glutamyl ◽  
Liver And Kidney ◽  
G 14

The synthesis of ophthalmic acid, an analogue of glutathione, was studied in vivo in mouse liver and kidney after administration of either L-alpha-aminobutyrate or L-gamma-glutamyl-L-alpha-aminobutyrate as precursor. L-alpha-aminobutyrate accumulated to a much greater extent, and induced a much greater synthesis of ophthalmic acid in the liver than in the kidney. In contrast, L-gamma-glutamyl-L-alpha-aminobutyrate initiated a large and more rapid synthesis of ophthalmic acid in the kidney than in the liver. Experiments with L-gamma-[G(-14)C]glutamyl-L-alpha-aminobutyrate showed that, although part of the dipeptide is degraded to its constituent amino acids, a significant proportion is directly incorporated into kidney ophthalmic acid. In contrast L-gamma-glutamyl-L-alpha-aminobutyrate serves poorly as a direct precursor of liver ophthalmic acid. The present results show that kidney gamma-glutamyl tripeptide synthesis can proceed directly from an exogenous gamma-glutamyl dipeptide precursor.

scholarly journals In Vivo Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa Arising by AmpC- and Non-AmpC-Mediated Pathways

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Erik Skoglund ◽  
Henrietta Abodakpi ◽  
Rafael Rios ◽  
Lorena Diaz ◽  
Elsa De La Cadena ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Genome Sequencing ◽  
Genetic Basis ◽  
The Other ◽  
Whole Genome ◽  
Apparent Loss ◽  
Lactamase Inhibitor ◽  
Hydrolysis Activity

Two pairs of ceftolozane/tazobactam susceptible/resistant P. aeruginosa were isolated from 2 patients after exposure to β-lactams. The genetic basis of ceftolozane/tazobactam resistance was evaluated, and β-lactam-resistant mechanisms were assessed by phenotypic assays. Whole genome sequencing identified mutations in AmpC including the mutation (V213A) and a deletion of 7 amino acids (P210–G216) in the Ω-loop. Phenotypic assays showed that ceftolozane/tazobactam resistance in the strain with AmpCV213A variant was associated with increased β-lactamase hydrolysis activity. On the other hand, the deletion of 7 amino acids in the Ω-loop of AmpC did not display enhanced β-lactamase activity. Resistance to ceftolozane/tazobactam in P. aeruginosa is associated with changes in AmpC; however, the apparent loss of β-lactamase activity in AmpC∆7 suggests that non-AmpC mechanisms could play an important role in resistance to β-lactam/β-lactamase inhibitor combinations.

scholarly journals Differential stringent control of Escherichia coli rRNA promoters: effects of ppGpp, DksA and the initiating nucleotides

Microbiology ◽  
2011 ◽  
Vol 157 (10) ◽  
pp. 2871-2879 ◽  
Author(s):  
Tim Kolmsee ◽  
Denis Delic ◽  
Tommy Agyenim ◽  
Christian Calles ◽  
Rolf Wagner
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Normal Growth ◽  
The Other ◽  
Stringent Control ◽  
Concerted Activity ◽  
Nucleoside Triphosphates

Transcription of rRNAs in Escherichia coli is directed from seven redundant rRNA operons, which are mainly regulated by their P1 promoters. Here we demonstrate by in vivo measurements that the amounts of individual rRNAs transcribed from the different operons under normal growth vary noticeably although the structures of all the P1 promoters are very similar. Moreover, we show that starvation for amino acids does not affect the seven P1 promoters in the same way. Notably, reduction of transcription from rrnD P1 was significantly lower compared to the other P1 promoters. The presence of DksA was shown to be crucial for the ppGpp-dependent downregulation of all P1 promoters. Because rrnD P1 is the only rrn promoter starting with GTP instead of ATP, we performed studies with a mutant rrnD promoter, where the initiating G+1 is replaced by A+1. These analyses demonstrated that the ppGpp sensitivity of rrn P1 promoters depends on the nature and concentration of initiating nucleoside triphosphates (iNTPs). Our results support the notion that the seven rRNA operons are differentially regulated and underline the importance of a concerted activity between ppGpp, DksA and an adequate concentration of the respective iNTP.

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