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)

Subcellular fraction (brush border, mitochondria, microsomes and plasma membranes) are isolated from the rat intestinal epithelial cells. A comparison was made between the effect of cold storage, freeze-thawing, heating and of some chemicals (DMSO, DTT, glycerol, sucrose) on the stability of Mg2+ and (Na+-K+) dependent ATPases in these fractions in order to determine possible difference linked to the localization in the enterocyte. Enzymatic activities were found more stable at -20 degrees C than at +4 degrees C. Microsomal (Na+-K+)-ATPase increased in activity until the 8th day, then declined. Brush border (Na+-K+)-ATPase was the least resistant of all fractions. For Mg2+-ATPase, that from mitochondria was that had lost much more activity (84%) in 15 days at +4 degrees C. With freeze-thawing there was a comparable decrease in all activities (20-35%). by heating between 35 and 60 degrees C, Mg2+-ATPase was shown to be more heat resistant than (Na+-K+)-ATPase. The addition of some stabilizing chemicals (DMSO, glycerol, sucrose) improved the heat stability of the two enzymes: better results were obtained with glycerol for Mg2+-ATPase and sucrose for (Na+-K+)-ATPase. These differences might be due to the compositon in membraine lipids or to the nature of the enzymes studied.
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PMID:Studies on intestinal adenosine triphosphatases. II. Stabilitiies in different rat subcellular fractions. 14 Aug

The activity of two membrane-bound enzymes of human platelets subjected to DMSO and a freezing-thawing process were analysed. Following treatment of fresh platelets with DMSO (5-20%) quantitative differences of AChE and 'ecto-ATPase' activities were seen. After cryopreservation of platelets in 5% DMSO the enzymatic activities of AChE and Mg2+-ATPase were no different from those obtained for fresh platelets. The lack of any changes in the activities of the enzymes of frozen platelets subjected to a washing procedure to remove DMSO, indicates that the mechanism of the DMSO-induced effect is reversible and that freezing-thawing process had no additional detrimental effects.
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PMID:Effect of DMSO and a freezing-thawing process on the 'ecto-ATPase' and AChE activities of human platelets. 294 81

Ouabain-sensitive (Na+ + K+)-ATPase activity in the rat myometrial microsome fraction could only be determined following detergent treatment. The (Na+ + K+)-ATPase activity manifested by detergent treatment proved very stable even to high concentrations of NaN3, in contrast Mg+-ATPase activity was reduced to about 30 percent of the control. The major part of the Mg2+-ATPase in the myometrial membrane preparation was found to be identical with the NaN3-sensitive ATP diphosphohydrolase capable of ATP and ADP hydrolysis. This monovalent-cation-insensitive ATP hydrolysis could be extensively reduced by DMSO. Furthermore DMSO prevented the inactivation of the (Na+ + K+)-ATPase activity. 10-100 microM Ca2+ inhibited the (Na+ + K+)-ATPase activity obtained in the presence of SDS by 15-50 percent. The Ca2+ sensitivity of the enzyme was considerably decreased if the proteins solubilized by the detergent had been separated from the membrane fragments by ultracentrifugation. The inhibitory effect could be regained by combining the supernatant with the pellet. Ca2+ sensitivity of the (Na+ + K+)-ATPase activity was preserved even after removal of the solubilized proteins provided that DMSO had been applied. It appears that a factor in the plasma membrane solubilized by SDS may be responsible for the loss of Ca2+ sensitivity of the (Na+ + K+)-ATPase activity, the solubilization of which can be prevented by DMSO.
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PMID:Myometrial (Na+ + K+)-activated ATPase and its Ca2+ sensitivity. 299 86