title: Studies on intestinal adenosine triphosphatases. II. Stabilitiies in different rat subcellular fractions.
abstract: 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.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D004355:Drug Stability; D004789:Enzyme Activation; D007413:Intestinal Mucosa / Q000201:enzymology; D007421:Intestine, Small / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008861:Microsomes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium