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)

The enzyme pattern in gastrocnemius muscle tissue was studied in 39 patients with peripheral arterial insufficiency. Phosphofructokinase and glucose-6-phosphate-dehydrogenase were significantly increased in the skeletal muscles from these patients. The most pronounced changes were found in 3-OH-acyl-CoA-dehydrogenase, citrate synthase, and in cytochrome-c-oxidase. These enzyme activities were increased by 60, 40 and 25 per cent respectively. In patients with claudication as the only symptom, the metabolic capacity was generally increased in skeletal muscles affected by the low blood flow. With increasing severity of arterial insufficiency, all enzyme activities decreased and glycolytic enzymes were affected first. 3-OH-acyl-CoA-dehydrogenase, citrate synthase and cytochrome-c-oxidase activities were still comparatively high in patients with gangrenous foot ulcers, indicating some maintenance of the muscle viability even in situations with very low blood flow.
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PMID:Enzyme activities in skeletal muscles from patients with peripheral arterial insufficiency. 100 44

The adaptation of enzyme activities, notably in the oxidative metabolism, and of prerequisites for tissue transport of oxygen in the claudication leg was evaluated by comparing muscle biopsies from the gastrocnemius muscle of the claudication and the symptom-free leg of seven patients with unilateral claudication. The claudication leg had higher activities of a marker enzyme for mitochondrial oxidative capacity, citrate synthase (CS), as well as of the MB and the mitochondrial isoenzyme of creatine kinase (CK), which are considered to be involved in the transfer of high energy phosphate from the mitochondria to the resynthesis of ATP in the cytoplasm. The difference between claudication and healthy leg in activities of these CK isoenzymes were well correlated with the corresponding side difference in CS activity. No significant differences between claudication and healthy leg were found in distribution of muscle fibre types or fibre dimension, capillary density or myoglobin content, nor was there any side difference in phosphofructokinase or lactate dehydrogenase. Side differences tended to be greater in those patients with the most advanced obstructive arterial disease as estimated from non-invasive pressure measurements. It is concluded that in reasonably physically-active patients, the mode of ischaemia to which the claudication leg is subjected leads to a metabolic adaptation characterized by increased activities of enzymes involved in the oxidative metabolism, but no significant adaptation of either the conditions for local oxygen transport, as estimated by myoglobin content, and capillary density, or capacity for anaerobic metabolism.
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PMID:Calf muscle adaptation in intermittent claudication. Side-differences in muscle metabolic characteristics in patients with unilateral arterial disease. 296 71

Patients with symptomatic peripheral arterial occlusive disease have a claudication-limited peak exercise performance that is improved with exercise training. The effects of training on skeletal muscle metabolism were evaluated in 26 patients with claudication, randomized into a 12-wk program of treadmill training (enhances muscle metabolic activity in normal subjects), strength training (stimulates muscle hypertrophy in normal subjects), or a nonexercising control group. Gastrocnemius muscle biopsies were performed at rest and before and after training. After 12 wk, only treadmill training improved peak exercise performance and peak oxygen consumption. Treadmill training did not alter type I or type II fiber area and did not increase citrate synthase activity but was associated with an increase in the percentage of denervated fibers (from 7.6 +/- 5.4 to 15.6 +/- 7.5%, P < 0.05). Improvement in exercise performance with treadmill training was associated with a correlative decrease in the plasma (r = -0.67) and muscle (r = -0.59) short-chain acylcarnitine concentrations (intermediates of oxidative metabolism). Patients in the strength and control groups had no changes in muscle histology or carnitine metabolism, but strength-trained subjects had a decrease in citrate synthase activity. Thus treadmill training increased peak exercise performance, but this benefit was associated with skeletal muscle denervation and the absence of a "classic" mitochondrial training response (increase in citrate synthase activity). The present study confirms the relationship between skeletal muscle acylcarnitine content and function in peripheral arterial occlusive disease, demonstrating that the response to treadmill training was associated with parallel improvements in intermediary metabolism.
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PMID:Effect of exercise training on skeletal muscle histology and metabolism in peripheral arterial disease. 887 46

Muscle mitochondrial content is tightly regulated, and requires the expression of both nuclear and mitochondrial genes. In addition, muscle mitochondrial content is a major determinant of aerobic exercise capacity in healthy subjects. The current study was designed to test the hypothesis that in healthy humans, muscle mitochondrial DNA (mtDNA) content is correlated with citrate synthase activity (a representative nuclear-encoded mitochondrial enzyme) and aerobic exercise capacity as defined by whole-body peak oxygen consumption (VO2). Furthermore, it was postulated that these relationships might be altered with disease. Twelve healthy and five paraplegic subjects underwent exercise testing and vastus lateralis muscle biopsy sampling. An additional ten healthy subjects and eight patients with unilateral peripheral arterial disease (PAD) underwent exercise testing and gastrocnemius muscle biopsy sampling. Citrate synthase activity and mtDNA content were positively correlated in the vastus lateralis muscles from the healthy subjects. This relationship was similar in muscle from paraplegic subjects. mtDNA content was positively correlated with peak VO2 in the healthy subjects and in the paraplegic subjects in whom peak VO2 had been elicited by functional electrical stimulation of the muscle. In contrast, the PAD subjects demonstrated higher mtDNA contents than would have been predicted based on their claudication-limited peak VO2. Thus, in healthy humans there are strong relationships between muscle mtDNA content and both muscle citrate synthase activity and peak VO2. These relationships are consistent with coordinant nuclear DNA and mtDNA expression, and with mitochondrial content being a determinant of aerobic exercise capacity. The relationships seen in healthy humans are quantitatively similar in paraplegic patients, but not in patients with PAD, a disease which is associated with a metabolic myopathy. The relationships between mtDNA content, mitochondrial enzyme activities and exercise capacity provide insight into the physiologic and pathophysiologic regulation of muscle mitochondrial expression.
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PMID:Relationships between muscle mitochondrial DNA content, mitochondrial enzyme activity and oxidative capacity in man: alterations with disease. 1036 19