Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.1.1 (hexokinase)
 5,274 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two main groups of quantitative methods are used in the brain to relate enzymatic processes to cellular structures, i.e. the methods of microchemistry and microscopic histochemistry. Microchemistry tries to quantify enzyme activities in very small brain regions by miniaturizing biochemical methods, whereas microscopic histochemistry applies staining procedures to tissue sections, preserving the structural relationship that is present in situ and giving topological information on the distribution of enzymes which is indispensable in structural heterogeneous tissue as is the brain. The present review deals preferentially with microscopic methods and, in particular, with scanning microphotometry (image plane scanning). Using this technique two measuring procedures can be applied for the quantification of enzyme activities, i.e. end-point and kinetic (continuous monitoring) measurements which are described in detail. Methods for the microphotometric demonstration of certain important dehydrogenases (isocitrate dehydrogenases, succinate dehydrogenase, NAD-linked malate dehydrogenase, glutamate dehydrogenase and glycerol 3-phosphate dehydrogenase), of cytochrome c oxidase, hexokinase and acetylcholinesterase are presented. These methods were adapted for giving optimal demonstration of enzyme activities in the rat hippocampus. The examples are given to illustrate the aptitude and possibilities of this technique in the quantification of enzymes in the complex matrix of the brain.
 ...
PMID:Quantitative enzyme histochemistry in the brain. 306 15

A cyclic pathway of NADPH generation involving interconversion of mannitol and fructose has been proposed to occur in fungi. In Aspergillus nidulans three enzymes of this proposed mannitol cycle (hexokinase, NADP-mannitol dehydrogenase and mannitol-l-phosphate phosphatase) were shown to be localized exclusively in the cytosol. Two isoenzymes of the fourth enzyme (mannitol-l-phosphate dehydrogenase) were detected and shown to be localized respectively in the mitochondrion and the cytosol. The mitochondrial isoenzyme appeared to be present on the outer face of the inner mitochondrial membrane. No evidence was found for a coordinated change in the maximal activities of the enzymes of the proposed mannitol cycle in extracts prepared from mycelia grown on six different carbon, and three different nitrogen sources nor for any increase in these activities induced by growth on NO3-. Studies of this type in which other NADP-linked dehydrogenases were measured showed that for most carbon sources tested growth on NO3- increased the maximal activity of NADP-isocitrate dehydrogenase as well as that of glucose-6-phosphate and 6-phosphogluconate dehydrogenases but had little effect on the maximal activity of NADP-malate dehydrogenase (decarboxylating). Our studies provide no support for the operation of the mannitol cycle, or for the proposed role of this cycle in NADPH generation in A. nidulans.
 ...
PMID:NADPH generation in Aspergillus nidulans: is the mannitol cycle involved? 314 71

Tibialis anterior (TA) muscle of mouse, rat, guinea pig, and rabbit was indirectly stimulated for 10 h/day at 10 Hz up to 28 days. Changes in the activity levels of hexokinase (HK), phosphofructokinase (PFK), glyceraldehydephosphate dehydrogenase (GAPDH), lactate dehydrogenase (LDH), creatine kinase (CK), citrate synthase (CS), malate dehydrogenase (MDH), 3-hydroxyacyl-CoA dehydrogenase (HADH), and beta-hydroxybutyrate dehydrogenase (HBDH) were compared. Although the direction of changes in the enzyme activity pattern was in accordance with previous findings on rabbit TA, the magnitude of the responses varied markedly between the mammals under study. Mouse TA was almost unaffected. A major effect of chronic stimulation in rat, guinea pig and rabbit was an increase in enzyme activities of aerobic-oxidative metabolism. According to intrinsic differences of the muscles under study, the increases varied among the species and appeared to be inversely related to the basal levels of these enzymes in the unstimulated muscles. Conversely, glycolytic enzyme activities (PFK, GAPDH, LDH) markedly decreased in rat, guinea pig, and rabbit, and were only slightly reduced in mouse. Changes in HK and HBDH activities displayed the largest variations in the induced change between species. These results indicate species-specific patterns of metabolic adaptation to increased contractile activity.
 ...
PMID:Species-specific effects of chronic nerve stimulation upon tibialis anterior muscle in mouse, rat, guinea pig, and rabbit. 317 88

The effect of hypoxia and post-hypoxic recovery were studied in gastrocnemius muscle of young-adult and mature beagle dogs. Furthermore, the possible interference of pharmacological treatment with nicergoline was evaluated in these conditions. Muscular glycolytic fuels, intermediates and end-products (glycogen, glucose, glucose 6-phosphate, pyruvate, lactate), Kreb's cycle intermediates (citrate, alpha-ketoglutarate, succinate, malate) and related free amino acids (glutamate, alanine), ammonium ion, energy store and mediators (ATP, ADP, AMP and creatine phosphate), and the energy charge potential were evaluated. Furthermore, in the crude extract and/or mitochondrial fraction of another portion of the same gastrocnemius muscle the maximum rate (Vmax) of some muscular enzymes related to the anaerobic glycolytic pathway (hexokinase, lactate dehydrogenase), the Kreb's cycle (citrate synthase, malate dehydrogenase), the aminoacid pool related to the Krebs' cycle (glutamate dehydrogenase and aspartate aminotransferase), the electron transfer chain (cytochrome oxidase) and NAD+/NADH exchanges (total NADH cytochrome c reductase) was evaluated. Some glycolytic metabolites and Krebs' cycle intermediates were modified by acute hypoxia, while free amino acids and energy mediators remained practically unchanged. The pharmacological treatment maintained the glucose and succinate muscular concentrations within the normal range, during hypoxia. The behaviour of muscular metabolites during hypoxia and/or post-hypoxic recovery is an age-related event. In fact, only in young-adult animals did the altered values return to normal in post-hypoxic recovery. In the present experimental conditions, only minor changes were observed as far as muscular enzyme activities are concerned. In any case, some enzyme activities tested showed different Vmax in young-adult dogs in comparison with mature ones.
 ...
PMID:Effect of hypoxia, aging and pharmacological treatment on muscular metabolites and enzyme activities. 322 9

Isoenzyme patterns of 63 isolates of Trichomonas vaginalis obtained in Vancouver were evaluated by use of thin-layer starch-gel electrophoresis. We attempted to use eight enzymes, but only four gave reproducible and interpretable results. There were four patterns with malic enzyme, two with malate dehydrogenase, one with hexokinase, and four with lactate dehydrogenase. The isoenzyme patterns of the 63 isolates were classified into 15 groups, but 49 (78%) fell into five groups and 14 (22%) fell into ten groups. There was no obvious correlation between groups and magnitude of symptoms and signs, past history of trichomoniasis, or likelihood of treatment failure. Results were consistent for isolates obtained from the same patient on different days. This system will allow differentiation of isolates into groups, a procedure that could be useful. However, groups do not appear to correlate with clinical or historical features or with outcome of treatment.
 ...
PMID:Isoenzyme patterns of isolates of Trichomonas vaginalis from Vancouver. 326 9

Sedentary subjects were submitted to repeated concentric isokinetic strength training protocols separated by a 50-day detraining period. Peak torque output of the quadriceps muscle group increased by 54% after the first ten-week training protocol. No significant changes in mean skeletal muscle fiber area were observed while a significant increase in percent fiber type and percent fiber area was noticed for type IIa fibers. The activities of the enzymes hexokinase, malate dehydrogenase, 3-hydroxyacyl CoA dehydrogenase, and oxoglutarate dehydrogenase were also increased significantly. Fifty days without training induced a significant decline in peak torque output. All the enzymes that responded to the first training protocol maintained their elevated activities over the detraining period except for the enzyme oxoglutarate dehydrogenase. A second training protocol administered to the same subjects following the 50-day inactivity period did not result in any significant increase in maximum torque output and fiber area. It is concluded that the isokinetic strength training protocol used can increase the functional capacity of skeletal muscle, but this effect does not appear to be related to skeletal muscle fiber hypertrophy.
 ...
PMID:Isokinetic strength training protocols: do they induce skeletal muscle fiber hypertrophy? 335 58

Eight enzymes, e.g. lactate dehydrogenase, malate dehydrogenase, fructose-diphosphate aldolase, sorbitol dehydrogenase, glucose-6-phosphate dehydrogenase, hexokinase, phosphofructokinase and pyruvate kinase were estimated quantitatively in the rat lens from 37 to 1,211 days of age, by spectrophotometric methods. The activity was expressed as mU/g LWW. All enzymes measured showed declining activities, but LDH, ALD, SDH, G-6-PDH, HK and PFK gave a significant decrease during ageing when plotted semi-logarithmically from 37 to 1,211 days. SDH and G-6-PDH showed a statistically significant difference between the enzymes from the male and the female lenses. The female lens always had a lower activity than the male lens. Of all enzymes the specific activity, expressed as mU/l mg protein, was calculated. This specific activity appeared to be rather constant during ageing, except for ALD. In the female lenses, the specific activity of 7 enzymes was lower than in the male lenses. For ALD the specific activity decreased significantly in the male lens from 5.32 at 37 days to 0.88 at 1,211 days. In the female lens this significant decrease was from 4.97 to 0.81.
 ...
PMID:The quantification of eight enzymes from the ageing rat lens, with respect to sex differences and special reference to aldolase. 340 13

Starch gel electrophoresis was used to examine the inheritance, expression, and linkage relationships among eight enzyme genes in the winter tick, Dermacentor albipictus. A fructose-specific hexokinase (FHK), adenylate kinase (ADK), and two forms of aconitase (ACON-A, ACON-C) appeared to have monomeric quaternary structures. A glycylleucine peptidase (PEP), isocitrate dehydrogenase (IDH), and anodally migrating malate dehydrogenase (MDH-A) were apparently dimers. The quaternary structure of glucose phosphate isomerase (GPI) could not be determined because of the similarity in relative mobility of the two available electromorphs. The genes for GPI, FHK, and ADK are located on the X chromosome in the following order: Adk - 37.4 - Gpi - 24.6 - Fhk, with Adk - Fhk being 46.5 map units apart. The remaining five genes were autosomally inherited. Of the 10 possible paired combinations of these genes, only the data for two pairs, Idh-Mdh (44.5% recombinants) and Acon-A--Acon-C (46.4% recombinants), suggested statistically significant linkage.
 ...
PMID:Expression, inheritance, and linkage relationships among eight enzyme genes in Dermacentor albipictus (Packard) (Acarina: Ixodidae). 358 75

The purpose of this study was to investigate the effects of repeated high-intensity intermittent training programs interspaced by detraining on human skeletal muscle and performances. First, nineteen subjects were submitted to a 15-week cycle ergometer training program which involved both continuous and high-intensity interval work patterns. Among these 19 subjects, six participated in a second 15-week training program after 7 weeks of detraining. Subjects were tested before and after each training program for maximal aerobic power and maximal short-term ergocycle performances of 10 and 90s. Muscle biopsy from the vastus lateralis before and after both training programs served for the determination of creatine kinase (CK), hexokinase, phosphofructokinase (PFK), lactate dehydrogenase (LDH), malate dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase (HADH) and oxoglutarate dehydrogenase (OGDH) activities. The first training program induced significant increases in all performances and enzyme activities but not in CK. Seven weeks of detraining provoked significant decreases in maximal aerobic power and maximal 90s ergocycle performance. While the interruption of training had no effect on glycolytic enzyme markers (PFK and LDH), oxidative enzyme activities (HADH and OGDH) declined. These results suggest that a fairly long interruption in training has negligeable effects on glycolytic enzymes while a persistent training stimulus is required to maintain high oxidative enzyme levels in human skeletal muscle. The degree of adaptation observed after the second training program confirms that the magnitude of the adaptive response to exercise-training is limited.
 ...
PMID:Effects of two high-intensity intermittent training programs interspaced by detraining on human skeletal muscle and performance. 365 91

The role of heredity in the response of maximal anaerobic capacities and skeletal muscle histochemical and biochemical characteristics to a 15-week cycle ergometer training program involving both continuous and interval work patterns was investigated in 14 pairs of monozygotic twins. The training program consisted mainly of series of ergocycle supramaximal exercises lasting from 15 s to 90 s and performed 4 and 5 times a week. The subjects were submitted to 10 s and 90 s all-out ergocycle tests to estimate maximal anaerobic alactacid (AAC) and lactacid (ALC) capacities, respectively. Muscle fiber types and creatine kinase (CK), hexokinase (HK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), malate dehydrogenase (MDH), 3-hydroxyacyl CoA dehydrogenase (HADH), and oxoglutarate dehydrogenase (OGDH) activities were determined in a biopsy from the vastus lateralis. Training increased AAC, ALC, fiber type I proportion, MDH, HADH, and OGDH (P less than 0.05) and decreased fiber type IIb proportion and the PFK/OGDH ratio. No significant change was observed for CK, HK, PFK, and LDH. Large interindividual differences in the response to training were observed for all variables. However, intraclass correlations indicated that the extent of the response of ALC and CK, HK, LDH, MDH, and OGDH activities and of the PFK/OGDH activity ratio to training were significantly similar within pairs of twins. Although the role of heredity appeared absent for the changes in fiber type proportions and in anaerobic alactacid capacity, the present results suggest that the response of anaerobic lactacid capacity and most enzyme activities to high-intensity intermittent training is significantly determined by the genotype.
 ...
PMID:Inheritance of human skeletal muscle and anaerobic capacity adaptation to high-intensity intermittent training. 373 13


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>