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)

To test whether repeated HBO exposures would increase activity of skeletal muscle metabolic enzymes, 27 rabbits (3 groups) were exposed 90 min/day, 5 days/wk to either 100% O2 at 243 kPa (HBO), 100% O2 at 101 kPa (HIO), or 21% O2 at 101 kPa (CON). Four animals per group were killed after 2 wk treatment, and the remaining five per group were killed after 8 wk of treatment. Soleus, plantaris, and tibialis anterior muscles were removed, and the activities of adenylate kinase, alpha-glycerophosphate dehydrogenase, and citrate synthase were measured. After 8 wk there was no difference in enzyme activity between groups for either plantaris or tibialis anterior. In the soleus after 8 wk there was no difference between groups in adenylate kinase activity, but alpha-glycerophosphate dehydrogenase activity was 56% greater (P < 0.05) in HBO than in HIO and 50% greater than in CON, and citrate synthase activity in HBO was 24% greater (P < 0.05) than that in HIO and 36% greater than that in CON. Inasmuch as the soleus is a postural muscle, these results suggest that long-term HBO treatments can increase enzyme activity in an actively contracting muscle.
Undersea Hyperb Med 1993 Sep
PMID:Skeletal muscle metabolic enzymes are altered by hyperbaric oxygenation treatments. 840 Nov 48

The purpose of the present study was to compare tissue oxidative capacity, skeletal muscle fatty acid composition, and tissue fuel stores in low-fat fed (LFD, 12% of energy from corn oil) male Wistar rats, and in high-fat fed (45% of energy from corn oil) obesity-prone (OP) and obesity-resistant (OR) male Wistar rats. Designation of OP and OR rats was based on body weight gain (upper tertile for OP; lower tertile for OR) after 5 weeks on the high-fat diet. Body weight gain over the 5-week dietary period was 91 +/- 9 g in LFD, 98 +/- 4 g in OR, and 158 +/- 5 g in OP (p < 0.05 vs. LFD and OR). Energy intake over the 5-week dietary period was 3099 +/- 101 kcal in LFD, 3185 +/- 51 kcal in OR, and 3728 +/- 45 kcal in OP (p < 0.05 vs. LFD and OR). Maximal citrate synthase activity (mumol.g-1.min-1) in the gastrocnemius muscle was not significantly different among groups: 12.1 +/- 2.4 in LFD, 11.4 +/- 1.9 in OR and 13.3 +/- 2.5 in OP rats. Similarly, citrate synthase activity in the heart, 59.3 +/- 7.2, and liver, 6.6 +/- 0.4, was also not significantly different among groups. Fatty acid composition of the gastrocnemius muscle was not significantly different among groups. Fasting glycogen levels in the liver, gastrocnemius muscle, and heart were 6.4 +/- 3.7, 13.2 +/- 2.3 and 6.8 +/- 1.9 mumol/g in LFD, 21.2 +/- 5.1 (p < 0.05 vs.(ABSTRACT TRUNCATED AT 250 WORDS)
Obes Res 1995 Sep
PMID:Tissue oxidative capacity, fuel stores and skeletal muscle fatty acid composition in obesity-prone and obesity-resistant rats. 852 Nov 65

Voluntary wheel running for 4 or 8 wk was used to assess whether a volitional training stimulus would induce adaptations in the oxidative capacity [citrate synthase activity (CS)], glucose phosphorylation capacity [hexokinase activity (HK)], and glucose transporter protein level (GLUT-4) of rat respiratory muscles. Running distances averaged approximately 10-13 km/day over the final 5 wk of training. Peak oxygen consumption by the trained animals was 17% greater (P < 0.05) than by age-matched sedentary control animals after 8 wk. CS, HK, and GLUT-4 in soleus and plantaris muscles all increased because of exercise training. CS increased in the rectus abdominis (+17%), external oblique (+28%), and internal oblique (+17%) but not in the costal or crural diaphragm after 4 wk of training. However, after 8 wk, CS in the costal diaphragm was 39% greater than control but was unchanged in the crural diaphragm. Whereas HK was significantly greater than control in the costal diaphragm (+18%) and rectus abdominis (+54%) after 4 wk, 8 wk of running were required for increases in HK in the external oblique (+17%) and internal oblique (+14%). HK in the crural diaphragm was not significantly altered by the exercise training. GLUT-4 did not change significantly in any of the respiratory muscles studied. These results indicate that significant adaptations in the glucose phosphorylation capacity and oxidative capacity of both inspiratory and expiratory muscles can take place in response to voluntary exercise. However, this same stimulus is not sufficient to cause an adaptive response in GLUT-4 protein level in these respiratory muscles.
J Appl Physiol (1985) 1995 Sep
PMID:Metabolic responses of rat respiratory muscles to voluntary exercise training. 856 34

The heat-shock protein Cpn60 (chaperonin, GroEL homologue) from the phototrophic bacterium Rhodobacter capsulatus B10 was purified to homogeneity and biochemically characterized. Native Cpn60 from R. capsulatus was shown to be a tetradecamer of 840 kDa similar to that of homologous chaperones characterized so far. Cpn60 possesses ATPase activity and promotes refolding of chaotropically denatured citrate synthase. The groESL operon of R. capsulatus was cloned using a degenerate oligonucleotide and sequenced. Two open reading frames (285 and 1,635 bp) were found; they encode Cpn10 and Cpn60, with corresponding deduced molecular masses of 10.6 and 57.6 kDa. The deduced amino acid sequences coincided perfectly with those of the amino terminus and of three tryptic peptides of purified Cpn60 from R. capsulatus. Strong evidence that R. capsulatus encodes only one copy of the groESL operon was obtained. Primer-extension analysis revealed that the groESL operon is transcribed by a -35/-10-type promoter, and that transcription was initiated from the same positions before and after heat-shock under both chemotrophic and phototrophic conditions. The major initiation site is immediately followed by the inverted repeat structure CIRCE, which has been found upstream of many bacterial heat-shock operons. A second minor transcript starts just after the CIRCE element. Although heat-shock induction of a groEL-lacZ fusion failed because of thermal inactivation of the fusion protein, Western blot analysis revealed a two- to threefold induction of cellular Cpn60 levels 45-75 min after shifting from 28 degrees C to 39 degrees C. Deletion mapping of the groESL promoter identified upstream of the promoter a 19-bp element that enhances groESL transcription eightfold and contains the AT-rich sequence dAAATTTTT, which is found at similar positions in heat-shock operons of other gram-negative bacteria.
Arch Microbiol 1996 Sep
PMID:Molecular analysis of the Rhodobacter capsulatus chaperonin (groESL) operon: purification and characterization of Cpn60. 870 96

The alterations of superoxide dismutase iso-enzyme (Cu,Zn-SOD and Mn-SOD) activities, contents, and mRNA expressions with aging were studied in rat soleus muscle (SO) and extensor digitorum longus muscle (EDL). The activity and content of Cu,Zn-SOD in both muscles were significantly higher in old rats (24 months old) than in young rats (4 months old), whereas those of Mn-SOD showed no difference between young and old rats. After normalization to citrate synthase (CS) activity, however Mn-SOD/CS ratio in SO also showed the age-related increase. Moreover, the activities of other major antioxidant enzymes, glutathione peroxidase (GPX) and catalase (CAT), indicated age-related increases only in SO. As for the expressions of mRNAs for SOD iso-enzymes, that of Cu,Zn-SOD in either muscle showed no significant change with aging, unlike its activity and content, although that of Mn-SOD was decreased with aging only in EDL. Thus, aging appeared to raise the level of antioxidant enzyme system in rat skeletal muscle. However, the resistance of Cu,Zn-SOD and Mn-SOD to oxidative stress accompanied by aging was different, the former being obviously greater than the latter. Such changes also differed in muscle fiber type suggesting that fast-twitch fibers are more susceptible to age-related oxidative stress than slow-twitch fibers.
Mech Ageing Dev 1995 Sep 29
PMID:Alterations of superoxide dismutase iso-enzyme activity, content, and mRNA expression with aging in rat skeletal muscle. 871 78

Transcriptional regulation was demonstrated in Rickettsia prowazekii, an obligate intracytoplasmic bacterium. The level of citrate synthase (gltA) mRNA II, from promoter P2, was greater in the total RNA isolated from heavily infected L929 cells than in moderately infected L929 cells; conversely, the level of ATP/ADP translocase (tlc) mRNA was greater in moderately infected cells. The level of gltA mRNA I, from promoter P1, did not change under these conditions. The chemical half-lives of gltA mRNA II and tlc mRNA under these conditions were very similar.
J Bacteriol 1996 Sep
PMID:Transcriptional regulation in the obligate intracytoplasmic bacterium Rickettsia prowazekii. 880 50

The gene for gamma-glutamylcysteine synthetase (gshA) from Thiobacillus ferrooxidans was isolated from a family of cosmids by its ability to complement an Escherichia coli gshA trxA double mutant which was unable to grow on minimal medium lacking glutathione. The predicted sequence of the gamma-glutamylcysteine synthetase was found to have only 18% amino acid sequence identity to the equivalent enzyme from E. coli. In spite of this low sequence homology, concentrations of GSH in a cell extract prepared from the E. coli gshA trxA mutant containing the cloned gene were almost as high as in a cell extract prepared from a wild-type E. coli strain. The gshA gene was found to be physically and transcriptionally linked to the T. ferrooxidans gene for citrate synthase (gltA). The T. ferrooxidans and E. coli citrate synthases shared 37% amino acid sequence identity and the cloned T. ferrooxidans citrate synthase gene was able to complement an E. coli gltA mutant.
Microbiology (Reading) 1996 Sep
PMID:The gene for gamma-glutamylcysteine synthetase from Thiobacillus ferrooxidans has low homology to its Escherichia coli equivalent and is linked to the gene for citrate synthase. 882 22

Glyoxysomal citrate synthase in pumpkin is synthesized as a precursor that has a cleavable presequence at its N-terminal end. To investigate the role of the presequence in the transport of the protein to the microbodies, we generated transgenic Arabidopsis plants that expressed beta-glucuronidase with the N-terminal presequence of the precursor to the glyoxysomal citrate synthase of pumpkin. Immunogold labeling and cell fractionation studies showed that the chimeric protein was transported into microbodies and subsequently was processed. The chimeric protein was transported to functionally different microbodies, such as glyoxysomes, leaf peroxisomes, and unspecialized microbodies. These observations indicated that the transport of glyoxysomal citrate synthase is mediated by its N-terminal presequence and that the transport system is functional in all plant microbodies. Site-directed mutagenesis of the conserved amino acids in the presequence caused abnormal targeting and inhibition of processing of the chimeric protein, suggesting that the conserved amino acids in the presequence are required for recognition of the target or processing.
Plant Cell 1996 Sep
PMID:Targeting and processing of a chimeric protein with the N-terminal presequence of the precursor to glyoxysomal citrate synthase. 883 11

Currently, the genotypic identification of the spotted fever group (SFG) rickettsiae is based on restriction fragment length polymorphism analysis of PCR-amplified genes coding for the enzyme citrate synthase and the surface proteins rOmpA and rOmpB. A set of useful restriction endonucleases was found following comparison of Rickettsia rickettsii and R. prowazekii sequences. However, by using three PCR amplifications and four enzyme digestions with this set, it was impossible to differentiate between all of the known serotypes of the SFG rickettsiae. We amplified by PCR and sequenced using an automated laser fluorescent DNA sequencer a fragment of the gene encoding the protein rOmpA from 21 serotypes of the SFG rickettsiae. A 632-bp amplification product was obtained for most of the strains, although no product could be obtained by using R. akari, R. australis, R. helvetica, and R. bellii DNAs. We found a characteristic sequence for all strains studied except the two isolates of R. massiliae, isolates GS and Mtul. Using the software package BISANCE, we determined the restriction map of this fragment and identified five potentially useful endonucleases, RsaI, AluI, PstI, XbaI, and AvaII. We confirmed the computer analysis-derived profiles by PCR-restriction fragment length polymorphism analysis. The combination of the profiles obtained after digestion of the PCR product by RsaI and PstI allowed for the differentiation of 16 strains. The use of AluI and XbaI allowed for the characterization of R. parkeri and strain HA-91, respectively. R. africae and strain S were differentiated by AvaII digestion. Thus, using a single PCR amplification, we were able to differentiate all of the SFG rickettsiae whose ompA gene was amplified by PCR.
J Clin Microbiol 1996 Sep
PMID:Differentiation of spotted fever group rickettsiae by sequencing and analysis of restriction fragment length polymorphism of PCR-amplified DNA of the gene encoding the protein rOmpA. 886 58

In order to improve the determination of the activities of the enzyme complexes of the electron transport chain (ETC) in fibroblasts, we characterized the isolation of mitochondria and measured enzyme activities in mitochondrial preparations from fibroblasts of control subjects and patients with suspected mitochondrial cytopathy. The isolation procedure yielded 54% of the citrate synthase activity in fibroblasts, with a 6-fold enrichment in this mitochondrial marker enzyme. The activities of the complexes of the ETC were linear with time and with the mitochondrial protein concentration used. The coefficients of variation for the enzyme activities determined were in the range of 10% in mitochondria from identical fibroblast cultures and between 30 and 70% in mitochondria from different fibroblast cultures of the same or of different patients. Decreased activities of one or more enzyme complexes (defined as an activity below the 95% confidence limit of control values) were found in 15 of 22 patients investigated. When compared with activities obtained in liver or skeletal muscle obtained at autopsy, the results were identical in three but different in two patients. The studies show that the activities of the enzyme complexes of the ETC can be determined reliably and reproducibly in mitochondria isolated from fibroblasts and that the results obtained are potentially useful for the diagnosis of mitochondrial cytopathies in patients with suggestive symptoms and signs.
Clin Chim Acta 1996 Sep 30
PMID:Determination of the activities of the enzyme complexes of the electron transport chain in human fibroblasts. 887 40


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