muscle enzymes


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muscle enzymes

the table lists some of the most often-mentioned enzymes present in skeletal muscle, with their locations and functions. Apart from actomyosin and myosin ATPases which are associated with the contractile mechanism, they are by no means specific to muscle, being present and highly active also in other tissues. See also Krebs cycle, muscle fibre types.
Table 1: Muscle enzymes
Name SiteCatalyses…
Actomyosin ATPase (amATPase) myosin head groups hydrolysis (Mg-dependent and triggered by rise in [Ca2+]) of terminal phosphate group of ATP when head-group is in interaction with actin, releasing energy that powers force- generation. (Compare myosin ATPase)
Creatine kinase (CK) cytoplasm transfer of phosphate group from creatine phosphate to ADP, producing ATP and creatine. Isoenzymes can be distinguished in blood when either skeletal or cardiac muscle has been damaged.
Hexokinase (HK) cytoplasm 'capture' of glucose after uptake from the blood, by conversion to the impermeant glucose 6-phosphate, in type 1 muscle fibres, which utilize glucose directly.
Lactate dehydrogenase (LDH) cytoplasm reduction of pyruvate to lactate when oxygen tension is low, and the converse when it is high. Isoenzymes can be distinguished in blood when either skeletal or cardiac muscle has been damaged.
Myosin ATPase (mATPase) myosin head groups hydrolysis (Ca2+ dependent, Mg2+ independent) of terminal phosphate group of ATP by head group alone, not interacting with actin (so not contraction-producing: cf actomyosin ATPase). Basic histochemical marker for fast vs. slow fibres.
Phosphofructokinase (PFK) cytoplasm conversion of fructose 6-phosphate to fructose 1,6-diphosphate; rate-limiting for glycolysis, and sensitive to very many stimulatory and inhibitory influences.
Phosphorylase (PPL) cytoplasmremoval of hexose units, one at a time, from glycogen, to form glucose 1-phosphate: rate-limiting enzyme of, and histochemical marker for, glycogenolysis.
Pyruvate dehydrogenase (PDH) mitochondrial envelope oxidative decarboxylation of pyruvate (from cytoplasm) to form acetyl CoA, which thence feeds into tricarboxylic acid (Krebs) cycle
Sarcoplasmic reticulum ATPase (srATPase) SR membrane pumping of [Ca2+] back into SR after its electrically stimulated release
Succinate dehydrogenase (SDH) mitochondrial inner membrane oxidation of succinate to fumarate, in tricarboxylic acid (Krebs) cycle. Histochemical marker for aerobic capacity.
References in periodicals archive ?
also criticized the new ACP document because it does not mention lifestyle modification, and he took issue with ACP's conclusion that routine monitoring of liver function and muscle enzymes is not necessary except in specific circumstances.
Until 3 months after the normalization of muscle enzymes and cholesterol levels, the patient did not presented any alteration in laboratory exams.
Discontinuation of simvastatin and reduction of the sports activities was followed by a prompt continual lowering of the elevated muscle enzymes to normal values over a 2-week period.
He also took issue with ACP's conclusion that routine monitoring of liver function and muscle enzymes is not necessary except in specific circumstances, which was based on data suggesting that rates of elevated liver and muscle enzymes did not differ between statin and place-bo groups in the recent trials.
In fact, each correlated better with physician global assessments than either LD or AST alone (29), two serum muscle enzymes that have previously been found to be valuable in the assessment of juvenile DM disease activity (28).
If his muscle enzymes are high then he obviously wouldn't run.
It was found that the analysis prior to the competition was within normal parameters, while after the trial there was significant blood changes in the erythrocyte and leukocyte counts, in the muscle enzymes and in certain proteins.
A blood test showed his muscle enzymes to be a bit high, and if you're not right you can't go for the big races, so we had to give Kempton a miss.
Myopathy (muscle weakness or pain combined with a 10-fold increase in muscle enzymes and more severe than myalgia) was rare and unlikely to be dose related in Lipitor patients.
If you take blood samples from racing greyhounds after a race the levels of muscle enzymes (a measure of recovery post-race) don't return to normal for at least four or five days.
He gave himself a little tweak and his muscle enzymes were wrong last month, but it's all back to normal again and the ground shouldn't bother him on Sunday.