Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.2.13 (aldolase)
 3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The changes in the metabolite content in freeze-clamped livers of fed rats occurring on perfusion with 10mm-d-fructose have been examined. 2. The most striking effects of fructose were an accumulation of fructose 1-phosphate, as already known, up to 8.7mumol/g of liver within 10min, a loss of total adenine nucleotides (up to 35% after 40min) with a decrease in the ATP content to 23% within 10min, a sevenfold rise in the concentration of IMP to 1.1mumol/g and an eightfold rise of alpha-glycerophosphate to 1.1mumol/g. 3. There was a transient decrease in P(i) from 4.2 to 1.7mumol/g. Within 40min the P(i) content recovered to the normal value, probably because of an uptake of P(i) from the perfusion medium. 4. The degradation of the adenine nucleotides beyond the stage of AMP can be accounted for by the decrease of ATP and P(i). As ATP inhibits 5-nucleotidase, and as P(i) inhibits AMP deaminase any AMP arising in the tissue is liable to undergo dephosphorylation or deamination under the conditions occurring after fructose loading. 5. The content of lactate increased to 4.3mumol/g at 80min; pyruvate also increased and the [lactate]/[pyruvate] ratio remained within physiological limits. 6. The concentration of free fructose within the liver remained much below that in the perfusion medium, indicating that the rate of penetration of fructose into the tissue was lower than the rate of utilization. 7. The fission of fructose 1-phosphate by liver aldolase is inhibited by several phosphorylated intermediates, especially by IMP. This inhibition is competitive with a K(i) of 0.1mm. 8. The maximal rates of the enzymes synthesizing and splitting fructose 1-phosphate are about equal. The accumulation of fructose 1-phosphate on fructose loading is due to the inhibition of the fission of fructose 1-phosphate by the IMP arising from the degradation of the adenine nucleotides.
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PMID:The cause of hepatic accumulation of fructose 1-phosphate on fructose loading. 550 Mar 10

1. During late foetal and early post-natal development of rabbit skeletal muscle the total protein increased more rapidly than the non-protein nitrogen content per g. wet wt. 2. AMP-deaminase activity of rabbit leg muscles increased rapidly over the period 5-15 days after birth. In diaphragm muscle from the same animal the rapid increase to the adult enzymic activity took place at about the time of birth. 3. The rapid increase in AMP-deaminase activity of leg muscle occurred earlier in animals born relatively mature, such as the chick and guinea pig, than in animals less well developed at birth, such as the rabbit and rat. 4. The pattern of enzymic activity shown by AMP deaminase during development in diaphragm, leg and cardiac muscles in a given species was closely paralleled by those of adenylate kinase and creatine phosphokinase. 5. When young rabbits were encouraged to become active at an earlier stage than is normal, the rise in creatine-phosphokinase activity occurred at an earlier age than in the control animals. 6. The results suggest that the activity pattern of the muscle is an important factor in determining the time at which the activities of the enzymes of special significance for muscle rise sharply to the adult values. 7. Development in rabbit leg muscle also involved an increase in aldolase activity. The pattern of change was similar to that obtained with other enzymes studied.
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PMID:The enzymes of adenine nucleotide metabolism in developing skeletal muscle. 603 59

Several glycolytic enzymes exist in muscle as free and structure-bound forms. A fraction of hexokinase (HK) is associated with the outer mitochondrial membrane. Phosphofructokinase (PFK) and aldolase (ALD) bind to F-actin, and AMP deaminase (AMPase) interacts with myosin. Using low-frequency stimulation (10 Hz, 24 h/d), we studied in rat fast-twitch muscle effects of contractile activity on soluble and structure-bound forms of these enzymes. Phosphoglucose isomerase (PGI), a soluble enzyme, was also examined. Fractional extraction was applied to study the intracellular distribution of soluble and bound enzyme activities 5 min, 1 h, 3 h, 1 d, and 7 d after the onset of stimulation. Confirming previous findings, total HK activity increased 7-fold in 7-d-stimulated muscles, whereas PFK, ALD, and PGI were reduced, ranging between 55% and 80% of their normal activities. AMPase activity was unaltered. At the time points studied, no changes were found in the extraction behavior of PGI and AMPase. The fraction of bound ALD increased slightly (12%). However, the distribution of HK and PFK was markedly altered. Bound PFK increased from 50% in the control to 85% in 7-d-stimulated muscles. Bound HK rose from 52% to 83% during the same time period. The increase in PFK binding was steep and occurred mainly within the first minutes and hours. The increase in HK binding occurred with some delay, but was significant in muscles stimulated for more than 1 h. In view of the altered kinetic properties of F-actin-bound PFK (alleviated allosteric inhibition by ATP) and bound HK (elevated catalytic activity), these changes are interpreted as early responses to match the metabolic demands during maximal contractile activity imposed on a muscle not programmed for sustained activity: Enhanced binding of PFK serves to accelerate glycolytic flux immediately after the onset of stimulation, whereas mitochondrial binding of HK facilitates the phosphorylation of exogenous glucose when glycogen stores have been depleted.
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PMID:Effects of low-frequency stimulation on soluble and structure-bound activities of hexokinase and phosphofructokinase in rat fast-twitch muscle. 766 4

Present study investigates the effect of metal accumulation on antioxidant level and mitochondrial enzymes function in muscle of Oreochromis mossambicus. Metal accumulation in muscle upregulated stress marker malondialdehyde and the activity of different antioxidant enzymes with no significant alteration in glutathione system. Metal exposure to fish muscle decreased the activity of mitochondrial enzymes. AMP deaminase, aldolase, cytochrome C oxidase and lipoamide reductase showed positive correlation with acetylcholinesterase, glutathione reductase, reduced glutathione and glutathione peroxidase, but negative correlation with superoxide dismutase, catalase, glutathione S-transferase and thiobarbituric acid reactive substance. Analysis of these biomarkers clearly indicates the change in oxidative load in muscle tissues and provides insight to muscle response to the metal exposure. Therefore, the study outlines the potential use of biomarkers in context of muscle mitochondrial enzymes relating to oxidative processes that take place in the fish muscle following metal exposure and toxicity.
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PMID:Impact of Metal Toxicity on Oxidative Balance and Mitochondrial Enzyme Function in Muscle of Tilapia. 2950 Apr 95