Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.1.2 (glutamate dehydrogenase)
 4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pregnant rats of 19th and 21st days were given an acute nitrogen overload produced by an infusion of either 0.2 M ammonium acetate or 0.2 M glutamine. Metabolic adaptations to nitrogen excess were studied measuring--in fetomaternal unit--non-protein nitrogen content and the activities of enzymes related with ammonia metabolism. Maternal and fetal plasma urea levels were increased by ammonium acetate treatment. Glutamine overload increased more the amino acid content in the mothers than in conceptus. As response to ammonium acetate treatment, glutamate dehydrogenase activity in liver was more sensitive in pregnant than in nonpregnant rats, suggesting more nitrogen incorporation into amino acids in pregnancy. Regarding glutamine synthetase activity, both treatments had an opposite effect except in kidney. The adenylate deaminase activity of pregnant rats was inhibited similarly to nonpregnant rats by nitrogen overloads, but stronger after glutamine infusion. Placenta and fetal metabolism were adjusted, as the dams, to lack of ammonia production by nitrogen overloads and to glutamine synthesis by ammonium acetate infusion.
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PMID:Metabolic adaptations to nitrogen excess in late gestation in rat. 177 94

Five different insert-length cDNAs encoding for soluble placental tissue protein 18 (PP18) variants were isolated by screening a human placental cDNA library using monospecific anti-PP18 serum. Sequence analysis of the longest clone showed that the insert contains an open reading frame encoding for a 392 residue-long protein with a 27 amino acid mitochondrial targeting sequence. The mature protein-designated PP18a-is 41.264 kDa consisting of 365 residues and is identical to the previously isolated and characterized PP18 antigen described in 1985. We also found a new, alternatively spliced cDNA encoding for a 300 residue-long, 33.776 kDa protein, which was designated PP18b. Alignment search of the protein databank showed that PP18a is almost entirely identical to the human mitochondrial branched-chain aminotransferase, while PP18b is its newly discovered splicing variant. We detected the two PP18 variants in normal adult and fetal human tissues besides the mitochondrial (only PP18a) and cytosolic (only PP18b) fractions of term placenta with chemiluminescence Western blot analysis. The 41 kDa PP18a variant was expressed ubiquitously, while the 33 kDa PP18b variant was found in smaller amounts in nearly all tissues. Trace amounts of the variants were present in the sera of non-pregnant healthy controls, as well as in pregnant women, but there was no real change in serum levels during pregnancy. In conclusion, PP18 variants are not specific for the placenta. Aminotransferase activity of placental origin PP18 antigens was verified by structural analysis and by a coupled branched-chain aminotransferase/glutamate dehydrogenase assay.
Placenta
PMID:Molecular cloning and characterization of placental tissue protein 18 (PP18a)/human mitochondrial branched-chain aminotransferase (BCATm) and its novel alternatively spliced PP18b variant. 1117 Aug 29

Functional placental insufficiency results in impaired feto-placental exchange, and subsequently in fetal growth restriction (FGR). We hypothesized that reductions in placental amino acid transporter activities in FGR pregnancies may be accompanied by abnormal expression of placental ammonia-handling enzymes. Term placentas were obtained from growth restricted (N=11) and normal (N=17) human pregnancies, and examined for glutamate dehydrogenase (GDH), glutamine synthetase (GS) and glutaminase (GA) mRNA and protein expression. Northern and Western blots were normalized on human actin mRNA and protein expression. For GA, the presence of mRNA coding the kidney isoform, and the absence of mRNA coding the liver isoform of the enzyme were demonstrated in the human placenta. In FGR pregnancies, placental expression of GDH mRNA was reduced (P<0.05) compared to normal pregnancies (1.576+/-0.144 vs. 2.092+/-0.177, respectively; mean+/-SE), whereas GS and GA mRNA expression was not different between the two types of pregnancy. GDH protein expression were also reduced (P<0.05) in FGR placentas compared to normal placentas (1.055+/-0.079 vs. 1.322+/-0.053, respectively; mean+/-SE). The GS and GA protein expression was not different in FGR pregnancies. Our data indicate that in cases of FGR, glutamate-to-oxoglutarate transformation in the placenta is limited, yet glutamine synthesis from and decomposition to glutamate seems to be preserved. This may reflect down-regulation of GDH in response to decreased fetal liver output and reduced umbilical artery glutamate concentrations in human FGR pregnancies.
Placenta 2009 Jul
PMID:Expression of enzymes regulating placental ammonia homeostasis in human fetal growth restricted pregnancies. 1950 Aug 43