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

1. Crayfish (Procambarus clarki) myosin was obtained from abdominal flexor muscle. The Ca2+-ATPase activity of crayfish myosin was much lower than that of rabbit skeletal myosin. However, F-actin-activated Mg2+-ATPase of crayfish and its superprecipitation closely resembled those of rabbit skeletal myosin. This fact suggests that the ability of crayfish myosin to combine with F-actin is essentially the same as that of skeletal myosin, although the chemical structures of both the myosin molecules when involved in their Ca2+-ATPast activity must be different from each other. 2. Crayfish and rabbit skeletal myosins were subjected to SDS-polyacrylamide gel electrophoresis. Crayfish myosin was found to have one heavy chain and two distinct light chain components (CF-gl and CF-g2), which have molecular weights of 18,000 and 16,000, respectively. These light chains correspond in molecular weight to the light chains (SK-g2 and SK-g3) in rabbit skeletal myosin. 3. CF-g1 could be liberated from the crayfish myosin molecule reacting with 5,5'-dithio-bis (2-nitrobenzoic acid), (Nbs2), without recovery of ATPase activity by the addition of DTT. These properties are equivalent to those of SK-g2 in rabbit skeletal myosin, although Nbs2-treated crayfish myosin did not recover its ATPase activity at all.
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PMID:Myosin from abdominal flexor muscle in a crayfish, Procambarus clarki Girard. 15 14