Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.4.1.4 (glutamate dehydrogenase)
 4,358 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The catabolic, NAD-specific glutamate dehydrogenase (NAD-GDH) of Neurospora crassa is under carbon catabolite repression. Cells grown on a glycolytic carbon source, such as sucrose, have low basal levels of enzyme activity. Treatment of repressed cells with either polymyxin B or amphotericin B resulted in derepression of NAD-GDH. Derepression at the transcriptional level occurred very rapidly (within 30 min) in response to polymyxin B addition but reached a plateau within 2 h. Amphotericin B-induced derepression initiated more slowly but continued for at least 6 h, resulting in a specific activity comparable to that seen with cells transferred to glutamate as the sole carbon source. These antibiotics had no significant effect upon the activities of two constitutive enzymes, pyruvate kinase and malate dehydrogenase. Curiously, only polymyxin B treatment derepressed invertase, another catabolite-repressed enzyme. The addition of 100 mM KCl to the growth medium blocked derepression by both antibiotics, but the addition of 50 mM MgCl2 only annulled derepression by polymyxin B. The ergosterol-deficient erg-1 mutant, which is resistant to amphotericin B, did not derepress NAD-GDH when treated with this drug. These results are consistent with derepression resulting from interactions of these antibiotics with the plasma membrane.
 ...
PMID:Antibiotic-induced derepression of the NAD-specific glutamate dehydrogenase of Neurospora crassa. 282 59

We have previously shown that inositol-1,4,5-trisphosphate (IP3) releases Ca2+ from an intracellular calcium store in permeabilized acinar cells of rat pancreas (H. Streb et al., 1983, Nature (London) 306:67-69). This observation suggests that IP3 might provide the missing link between activation of the muscarinic receptor and Ca2+ release from intracellular stores during stimulation. In order to localize the intracellular IP3-sensitive calcium pool, IP3-induced Ca2+ release was measured in isolated subcellular fractions. A total homogenate was prepared from acinar cells which had been isolated by a collagenase digestion method. Endoplasmic reticulum was separated from mitochondria, zymogen granules and nuclei by differential centrifugation. Plasma membranes and endoplasmic reticulum were separated by centrifugation on a sucrose step gradient or by precipitation with high concentrations of MgCl2. IP3-induced Ca2+ release per mg protein in the total homogenate was the same as in leaky cells and was sufficiently stable to make short separation procedures possible. In fractions obtained by either differential centrifugation at 7000 X g, sucrose-density centrifugation, or MgCl2 precipitation there was a close correlation of Ip3-induced Ca2+ release with the endoplasmic reticulum markers ribonucleic acid (r = 0.96, 1.00, 0.91, respectively) and NADPH cytochrome c reductase (r = 0.63, 0.98, 0.90, respectively). In contrast, there was a clear negative correlation with the mitochondrial markers cytochrome c oxidase (r = -0.64) and glutamate dehydrogenase (r = -0.75) and with the plasma membrane markers (Na+ + K+)-ATPase (r = -0.81) and alkaline phosphatase (r = -0.77) in all fractions analyzed. IP3-induced Ca2+ release was distributed independently of zymogen granule or nuclei content of the fractions as assessed by electron microscopy. The data suggest that inositol-1,4,5-trisphosphate releases Ca2+ from endoplasmic reticulum in pancreatic acinar cells.
 ...
PMID:Effect of inositol-1,4,5-trisphosphate on isolated subcellular fractions of rat pancreas. 633 62

A two-step method for assaying creatinine in serum and urine samples, suitable with automated analyzers, is reported. Reagent 1, for the first step, contains a blanking system [creatine amidinohydrolase (CRTase), urease, glutamate dehydrogenase, NADPH, and 2-oxoglutarate] and a NADPH-regenerating system [Mg(2+)-dependent isocitrate dehydrogenase (ICD), MgCl2, and excess isocitrate]. Reagent 2, for the second step, contains the metal-chelating reagent trans-1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid (CyDTA) and a trigger system [creatinine amidohydrolase (CRNase)]. When a specimen is mixed with reagent 1, all the creatine, urea, and NH3 present are removed by the blanking and NADPH systems. On adding reagent 2, CyDTA inactivates ICD to inhibit the NADPH system. Simultaneously, the creatinine (1 mol) in the specimen is hydrolyzed into creatine by CRNase, and then releases NADP+ (2 mol) through the blanking system. Our optimized method can determine creatinine linearly up to 500 mg/L, with within-day CVs < 1.2% and day-to-day CVs < 2.7%.
 ...
PMID:Enzymatic rate assay of creatinine in serum and urine. 840 98