Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activation and inhibition of Ca2+-ATPase of calmodulin-depleted human erythrocyte membranes by oleic acid and a variety of other fatty acids have been measured. Low concentrations of oleic acid stimulate the enzyme activity, both in the presence and in the absence of calmodulin. Concomitantly, the affinity of the membrane bound enzyme to calmodulin progressively decreases due to competitive interactions of calmodulin and oleic acid with the enzyme. Removal of oleic acid from the membrane by serum albumin extinguishes the activating effect of oleic acid and restores the ability of the enzyme to bind calmodulin with high affinity. High concentrations of oleic acid induce an almost complete and irreversible loss of enzyme activity which cannot be abolished by removal of oleic acid. Despite a complete loss of enzyme activity, binding of calmodulin to membranes is approximately normal after removal of oleic acid. Activities of (Na+ + K+)-ATPase, Mg2+-ATPase and acetylcholine esterase, as well as the total protein content, show no gross changes upon treatment of membranes with increasing amounts of oleic acid, which seems to exclude that membrane solubilisation by oleic acid causes an inactivation of the enzyme.
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PMID:Effects of fatty acids on activity and calmodulin binding of Ca2+-ATPase of human erythrocyte membranes. 613 52

Although there is some evidence that extrachoroidal sites for the production of cerebrospinal fluid (CSF) are important, the choroid plexuses in the ventricles contribute the major part of CSF formation. The exact mechanism for CSF production is not fully understood. In order to study this mechanism from the enzyme histochemical standpoint, the previously reported studies are reviewed, in addition to the authors' own electron microscopic enzyme histochemical observations on this tissue. The ultrastructure and enzyme biochemistry of choroid plexus epithelial cells are considered, together with the histochemistry of the following enzymes: alkaline and acid phosphatase, Mg2+-ATPase, Na+, K+-ATPase, glucose-6-phosphatase, thiamine pyrophosphatase, adenylate cyclase, carbonic anhydrase, oxidoreductase, esterase, several hydrolases, and other enzymes. Finally, CSF formation and active transport in the choroid plexus epithelial cells are discussed, mainly in terms of the results of our enzyme cytochemical observations on Na+, K+-ATPase and carbonic anhydrase in this tissue.
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PMID:The enzyme histochemistry of the choroid plexus. 683 Nov 99

The catalytic properties of energy-utilizing ATPases enzyme systems related to ions homeostasis were evaluated in different types of synaptic plasma membranes (SPM) and in somatic plasma membranes (SM) from cerebral cortex of rats aged 5, 10, and 22 months. The following enzymes were evaluated: Na+, K+-ATPase, Ca2+, Mg2+-ATPase, Mg2+-ATPase and the activity of acetylcholine esterase (AChE) was also evaluated. The ATPases located on SM and SPM and synaptic vesicles are involved in the regulation of presynaptic nerve ending homeostasis and postsynaptic activities. Different types of SM and SPM (three types) were obtained by combinations of differential and density gradient ultracentrifugation techniques in sucrose-Ficoll media: the first was obtained by purification of the sediment of mitochondrial supernate and the second after synaptosomal lysis and purification on density gradient. In the cerebral cortex of 5-month-old rats, the catalytic properties of ATPases systems markedly differ according to the different types of SPM and SM, thus indicating that the metabolic role of each ATPase is determined by their subcellular in vivo localization. As regards ageing: (i) ATPase enzyme catalytic activities tend to decrease during ageing in a complex way; (ii) ageing induced specific modifications in individual ATPases according to their subsynaptic localization; and (iii) these effects are probably due to specific biochemical situations that take place at each age, reflecting the bioenergetic state of the cerebral tissue with respect to the energy demand. The cerebral concentration and content of SM proteins were increased by ageing suggesting that many defective noncatalytic proteins may be formed during ageing, as shown by immunoblotting techniques.
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PMID:ATPases enzyme activities during ageing in different types of somatic and synaptic plasma membranes from rat frontal cerebral cortex. 1185 24