The importance of glyoxylate and other glycine precursors in the hepatic and renal conjugation of benzoate in normal and hyperammonemic mice

1989 ◽  
Vol 67 (11) ◽  
pp. 1426-1430 ◽  
Author(s):  
Ijaz A. Qureshi ◽  
Paule Clermont ◽  
Jacques Letarte
Keyword(s):  
Amino Acid ◽  
Renal Cortex ◽  
Specific Activity ◽  
Cumulative Effect ◽  
Isolated Hepatocytes ◽  
Mean Value ◽  
The Body ◽  
Liver Homogenates ◽  
Amino Acid Precursors

Benzoate conjugation, represented by hippurate synthesis, was measured in hepatocytes isolated from normal and sparse-fur (spf) mutant mice, with X-linked ornithine transcarbamylase deficiency, to compare the effects of glyoxylate and piridoxylate (a hemiacetal of glyoxylate and pyridoxine), substituted for glycine. Various amino acid precursors of glycine described in the literature, including serine, threonine, glutamine, and glutamate, were studied in a similar manner. The role of glyoxylate and piridoxylate was also assessed in the renal cortex, in comparison with liver homogenates from normal and hyperammonemic mice. The results indicate the importance of glyoxylate and piridoxylate to completely substitute for glycine (96–115%) in isolated hepatocytes of spf/Y mice, as compared with 53–69% (p < 0.05) in normal +/Y controls. The mean value of amino acid precursors to substitute for glycine in spf mice was serine 51%, threonine 29% (p < 0.05), and glutamine 9%. In normal mice, only serine (21%) (p < 0.01) partly substituted for glycine, whereas threonine, glutamine and glutamate gave negative values of net hippurate synthesis. The specific activity of renal cortex for hippurate synthesis from glycine, glyoxylate and piridoxylate was 3–4 times that of liver homogenates (p < 0.01 – < 0.001). A scheme for the transamination of glyoxylate by alanine is presented. Besides alanine, the excess of glycine, serine, and threonine is readily deaminated in the body to take part in gluconeogenic reactions, thus contributing to hyperammonemia. The cumulative effect of benzoate conjugation to drain these ammoniagenic precursors through glycine may be the basis of its therapeutic effect in hyperammonemia.Key words: glycine, glyoxylate, sodium benzoate, hippurate synthesis, spf mice, hepatocytes.

scholarly journals Role of Integrase in Reverse Transcription of the Saccharomyces cerevisiae Retrotransposon Ty1

2005 ◽  
Vol 4 (6) ◽  
pp. 1057-1065 ◽  
Author(s):  
M. Wilhelm ◽  
F.-X. Wilhelm
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Specific Activity ◽  
Rnase H ◽  
Amino Acid Residues ◽  
Acidic Amino Acid ◽  
Acidic Domain ◽  
Basic Region

ABSTRACT Reverse transcriptase (RT) with its associated RNase H (RH) domain and integrase (IN) are key enzymes encoded by retroviruses and retrotransposons. Several studies have implied a functional role of the interaction between IN and RT during the replication of retroviral and retrotransposon genomes. In this study, IN deletion mutants were used to investigate the role of IN on the RT activity of the yeast Saccharomyces cerevisiae retrotransposon Ty1. We have identified two domains of Ty1 integrase which have effects on RT activity in vivo. The deletion of a domain spanning amino acid residues 233 to 520 of IN increases the exogenous specific activity of RT up to 20-fold, whereas the removal of a region rich in acidic amino acid residues between residues 521 and 607 decreases its activity. The last result complements our observation that an active recombinant RT protein can be obtained if a small acidic tail mimicking the acidic domain of IN is fused to the RT-RH domain. We suggest that interaction between these acidic amino acid residues of IN and a basic region of RT could be critical for the correct folding of RT and for the formation of an active conformation of the enzyme.

Detection of protein disulphide-isomerase in sheep pancreas fractions

1982 ◽  
Vol 2 (5) ◽  
pp. 343-349 ◽  
Author(s):  
David A. Hillson ◽  
Jacqueline Anderson
Keyword(s):  
Specific Activity ◽  
Protein Biosynthesis ◽  
Major Site ◽  
General Role ◽  
Protein Disulphide Isomerase ◽  
Isomerase Activity ◽  
Liver Homogenates ◽  
Specific Activities

Conclusions The use of diethylpyrocarbonate to inhibit endogenous ribonuclease in sheep pancreas allows the detection of protein-disulphide-isomerase activity in homogenates, at specific activities of up to 4 units/g. This is higher than the specific activity in sheep liver homogenates (about 2 units/g) or in homogenates of other sheep tissues (16). It is thus evident that high levels of protein-disulphide-isomerase activity are present in sheep pancreas. This is consistent both with the postulated general role of protein disulphide-isomerase in protein biosynthesis (10,11) and with the in vitro action of the enzyme on its conventional substrate scrambled ribonuclease, since pancreas is the major site of ribonuclease synthesis.

scholarly journals Type 3 Innate Lymphoid Cells as Regulators of the Host-Pathogen Interaction

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana Valle-Noguera ◽  
Anne Ochoa-Ramos ◽  
Maria José Gomez-Sánchez ◽  
Aranzazu Cruz-Adalia
Keyword(s):  
Transgenic Mice ◽  
Molecular Mechanisms ◽  
Specific Activity ◽  
Innate Lymphoid Cells ◽  
The Body ◽  
Lymphoid Cells ◽  
Intracellular Pathogens ◽  
Host Pathogen Interaction ◽  
Type 3

Type 3 Innate lymphoid cells (ILC3s) have been described as tissue-resident cells and characterized throughout the body, especially in mucosal sites and classical first barrier organs such as skin, gut and lungs, among others. A significant part of the research has focused on their role in combating pathogens, mainly extracellular pathogens, with the gut as the principal organ. However, some recent discoveries in the field have unveiled their activity in other organs, combating intracellular pathogens and as part of the response to viruses. In this review we have compiled the latest studies on the role of ILC3s and the molecular mechanisms involved in defending against different microbes at the mucosal surface, most of these studies have made use of conditional transgenic mice. The present review therefore attempts to provide an overview of the function of ILC3s in infections throughout the body, focusing on their specific activity in different organs.

8 Functional Role of Histidine in Diets of Young Pigs

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 13-13
Author(s):  
Jaap van Milgen ◽  
Nathalie Le Floc’h
Keyword(s):  
Amino Acid ◽  
Dose Response ◽  
The Body ◽  
Whole Body ◽  
Body Protein ◽  
Constituent Amino Acid ◽  
Young Pigs ◽  
Hydrolysis Of ◽  
The Brain

Abstract Histidine is a constituent amino acid of body proteins and, once incorporated in protein, histidine can be methylated post-translationally to methyl-histidine. Histidine is also a precursor of histamine, a neurotransmitter and involved in the immune response. Histidine and histamine are constituents of a number of dipeptides, which act as pH buffers, metal chelating agents, and anti-oxidants, especially in skeletal muscles and in the brain. A considerable fraction of whole-body histidine is present as carnosine, the dipeptide of histidine and β-alanine. In the longissimus muscle, about 40% of the total histidine content is present as carnosine. The histidine in carnosine can be methylated to anserine or balenine, and the pig is among the few species that synthesize both forms. Hydrolysis of body protein and of histidine-containing dipeptides results in the release of the constituent amino acids. However, only the histidine of protein and carnosine can be reused for protein synthesis. Methyl-histidine is either excreted in the urine or remains bound in the dipeptides and accumulates in the body. Because carnosine represents such a large histidine reservoir, a dietary histidine deficiency may not directly lead to a reduction in growth, especially if growth is given a higher priority for histidine utilization than maintaining or depleting the histidine-containing dipeptide reserves. Few histidine dose-response studies have been done in piglets and differences in the estimated requirements may be due to differences in diluting or depleting the dipeptide reserves. However, at low histidine intakes, both feed intake and growth are reduced and a reduction of the histidine-to-lysine supply by 1 percentage point results in a growth reduction of 4%. Histidine dose-response studies need to consider the role of histidine as a constituent amino acid of body protein as well as its role in dipeptides.

Role of pancreatic L-asparagine synthetase in homeostasis of L-asparagine.

1979 ◽  
Vol 236 (6) ◽  
pp. E746 ◽  
Author(s):  
H A Milman ◽  
D A Cooney ◽  
D M Young
Keyword(s):  
Amino Acid ◽  
Exocrine Pancreas ◽  
Specific Activity ◽  
Pancreatic Enzyme ◽  
High Specific Activity ◽  
Asparagine Synthetase ◽  
Mouse Pancreas ◽  
Normal Limits ◽  
Intravenous Treatment

L-Asparagine synthetase from mouse pancreas was found to be associated principally with the exocrine pancreas and to be dependent on the age of the animal, but not on gender, diet, or the presence of tumor under the conditions examined. The function of the pancreatic enzyme appears to be to supply L-asparagine for the synthesis of pancreatic proteins. This function is suggested by the high specific activity of L-asparagine in pancreatic proteins after intravenous treatment of BDF1 mice with L-[U-14C]asparatate. The pancreas is also able to function as a storage depot for L-asparagine under conditions in which the concentration of the amino acid in the blood is in excess. Unlike the liver, the pancreas is unable to add L-asparagine to the circulation when the concentration of the amide is below normal limits.

scholarly journals Involvement of d-amino acid oxidase in elimination of free d-amino acids in mice

1989 ◽  
Vol 257 (1) ◽  
pp. 291-292 ◽  
Author(s):  
Y Nagata ◽  
R Konno ◽  
Y Yasumura ◽  
T Akino
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Physiological Role ◽  
The Body ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Kidney Liver ◽  
Amino Acid Concentrations ◽  
Serum And Urine

The physiological role of D-amino acid oxidase was investigated by using mutant ddY/DAO- mice lacking the enzyme. Free D-amino acid concentrations in the mutant mice were significantly higher than those of control ddY/DAO+ mice in kidney, liver, lung, heart, brain, erythrocytes, serum and urine. The results suggest that the enzyme is involved in the catabolism of free D-amino acids in the body, and that free D-amino acids are also excreted into urine.

Glucose metabolism and bicarbonate turnover in dystrophic mice

1964 ◽  
Vol 207 (5) ◽  
pp. 1161-1165 ◽  
Author(s):  
Nome Baker ◽  
Robert Huebotter
Keyword(s):  
Specific Activity ◽  
Mean Value ◽  
Relative Increase ◽  
The Body ◽  
Whole Body ◽  
Littermate Control ◽  
Unit Body Weight ◽  
Total Glucose ◽  
Enzymatic Pathways ◽  
Dystrophic Mice

Hereditarily dystrophic and littermate control mice of the Bar Harbor strain 129 were injected with bicarbonate-C14 to compare rates of turnover of the body bicarbonate compartments. A separate group of dystrophic mice was also injected with glucose-U-C14 to study the turnover and oxidation to CO2 of body glucose. The total glucose pool size was also measured in four dystrophic mice and was found to be 50% greater per unit body weight than that of the previously published mean value for control mice. Since the plasma glucose concentration was the same in both groups, the increased glucose compartment size appears to reflect a relative increase in extracellular space. Specific activity-time curves of respiratory C14O2 were identical in both groups of mice after intravenous injection of bicarbonate-C14. Average values of plasma and whole body glucose specific activity 5–15 min after injection of glucose were lower than, but not significantly different from, those reported previously for control mice. The rate of formation of C14O2 from glucose-C14 was at least as fast in dystrophic mice as in controls. The data indicate that the enzymatic pathways involved in glycolysis, the citric acid cycle, glucogenesis, and gluconeogenesis are functionally active in this disease.

Sign in / Sign up

Export Citation Format

Share Document