Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We determined representative enzyme activities of glycogenolysis (glycogen phosphorylase) glycolysis (d-glyceraldehyde-3-phosphate dehydrogenase, GAPDH), beta oxidation of free fatty acids (1-3-hydroxyacyl CoA dehydrogenase, HADH), citric acid cycle (citrate synthase, CS), lactate fermentation (lactate dehydrogenase LDH), and creatine phosphate metabolism (creatine kinase, CK) in left ventricular samples of 36 patients to investigate if the metabolic capacities of the energy-supplying pathways are differently affected in different heart diseases. There were 17 patients with mitral valve diseases (MVD), 8 patients with aortic valve diseases (AVD), and 11 patients who suffered from dilative cardiomyopathies (DCM). The main metabolic characteristic on the level of enzymatic organization in patients with DCM was an increased ratio of GAPDH/HADH activities and a decreased ratio of HADH/CS activities compared to the valve-diseased patients. This result indicates that the capacity of glucose oxidation is enhanced at the expense of fatty acid metabolism in patients with DCM. Furthermore, we determined significantly lower myocardial CK activities in this group of patients, most probably reflecting a diminished content of myofibrils. Citrate synthase activity was lowest in patients with AVD. Although we cannot rule out that the impaired left ventricular function is in part responsible for the shift of the capacities of the energy-supplying metabolism in patients with DCM, we favor the assumption that it is a specific feature of this myocardial disease.
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PMID:Comparative analysis of myocardial enzyme activities of the energy-supplying metabolism in patients with dilative cardiomyopathies and valve diseases. 370 46

In female rats, ovariectomy (OVX) is associated with increased body fat and insulin resistance, and estradiol replacement prevents these alterations. These metabolic changes related to the estrogen-deficient state might be due, in part, to alterations in skeletal muscle substrate metabolism. We tested the hypothesis that estradiol affects the regulation of enzymes involved in substrate oxidation and storage within skeletal muscle. Specifically, we examined enzymes involved in the regulation of glycogen synthesis (glycogen synthase [GS]), glycolysis (phosphofructokinase [PFK]), tricarboxylic acid cycle activity (citrate synthase [CS]), and beta-oxidation (beta-hydroxyacyl-CoA dehydrogenase [beta-HADH]). Twenty-two, female Sprague-Dawley rats (7 to 8 weeks old) were separated into 3 groups: OVX + placebo (P; n = 8), OVX + estradiol (E(2); n = 8), and sham-operated (S; n = 6). Rats from E(2) and P groups were pair-fed to the S group to control for OVX-induced changes in food intake. After 16 days, activities of GS, PFK, CS, and beta-HADH were measured in vastus medialis muscle. GS fractional velocity was significantly lower (P <.05) in P (mean +/- SE; 39.7% +/- 6.2%) compared with both S (61.9% +/- 8.8%) and E(2) (65.8% +/- 8.4%) rats. In addition, E(2) rats (41.4 +/- 2.0) had significantly higher (P <.05) CS activity than P (34.9 +/- 2.0) and S (33.9 +/- 1.4 micromol/min/g) groups. There was no effect of OVX or estradiol replacement on beta-HADH or PFK. Our results suggest that, independent of alterations in food intake, estradiol availability affects the regulation of enzymes involved in nonoxidative glucose disposal (GS) and oxidative metabolism (CS) in skeletal muscle.
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PMID:Effect of ovariectomy and estradiol replacement on skeletal muscle enzyme activity in female rats. 1240 87

The objective of this study was to determine whether patients with chronic obstructive lung disease (COPD) display differences in organization of the metabolic pathways and segments involved in energy supply compared with healthy control subjects. Metabolic pathway potential, based on the measurement of the maximal activity (V(max)) of representative enzymes, was assessed in tissue extracted from the vastus lateralis in seven patients with COPD (age 67 +/- 4 yr; FEV(1)/FVC = 44 +/- 3%, where FEV(1) is forced expiratory volume in 1 s and FVC is forced vital capacity; means +/- SE) and nine healthy age-matched controls (age 68 +/- 2 yr; FEV(1)/FVC = 75 +/- 2%). Compared with control, the COPD patients displayed lower (P < 0.05) V(max) (mol.kg protein(-1).h(-1)) for cytochrome c oxidase (COX; 21.2 +/- 2.0 vs. 28.7 +/- 2.2) and 3-hydroxyacyl-CoA dehydrogenase (HADH; 2.54 +/- 0.14 vs. 3.74 +/- 0.12) but not citrate synthase (CS; 2.20 +/- 0.16 vs. 3.19 +/- 0.5). While no differences between groups were observed in V(max) for creatine phosphokinase, phosphorylase (PHOSPH), phosphofructokinase (PFK), pyruvate kinase, and lactate dehydrogenase, hexokinase (HEX) was elevated in COPD (P < 0.05). Enzyme activity ratios were higher (P < 0.05) for HEX/CS, HEX/COX, PHOSPH/HADH and PFK/HADH in COPD compared with control. It is concluded that COPD patients exhibit a reduced potential for both the electron transport system and fat oxidation and an increased potential for glucose phosphorylation while the potential for glycogenolysis and glycolysis remains normal. A comparison of enzyme ratios indicated greater potentials for glucose phosphorylation relative to the citric acid cycle and the electron transport chain and glycogenolysis and glycolysis relative to beta-oxidation.
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PMID:Organization of metabolic pathways in vastus lateralis of patients with chronic obstructive pulmonary disease. 1863 55