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1.
《The International journal of biochemistry》1994,26(7):905-911
- 1.1. Parotid plasma membrane nonpump low-affinity Ca2+-ATPase, which possesses high-affinity (Ca2+ + Mg2+ )-ATPase activity, was characterized.
- 2.2. Purified Ca2+-ATPase hydrolyzed the nucleoside triphosphates, GTP, ITP, CTP, UTP, TTP (67–93% of ATP) and nucleoside diphosphates, ADP. GDP, IDP, CDP, TDP (12–40% of ATP) but not AMP and p-NPP.
- 3.3. The maximum activities of Ca2+- and (Ca2+ +Mg2+ )-ATPases were obtained in the presence of 1 mM and 0.13 μ M Ca2+, respectively.
- 4.4. The Km values for Ca2+ in Ca2+- and (Ca2++ Mg2+ )-ATPases were 0.2 mM and 22 nM. respectively.
- 5.5. The activities of both Ca2+- and (Ca2+ + Mg2+ )-ATPases were found in the right-side-out-vesicles obtained from the plasma membrane-rich fraction.
- 6.6. These features suggest that Ca2+-ATPase is an ecto-Ca2+-dependent nucleoside triphosphatase.
2.
- 1.1. Ion dependence and vanadium-induced inhibition on branchial sac ATPase in five species of ascidian Phlebobranchiata (vanadium-accumulating) and Stolidobranchiata (iron-accumulating) were studied.
- 2.2. The ATPase was obtained from the microsomal fraction, which was prepared from each ascidian branchial sac.
- 3.3. The ATPase was dependent on Mg2+ and activated by exogenous Na+ + K+.
- 4.4. Ouabain inhibited the ATPase activity in vitro, 10 μM to 100 μM vanadate, in vitro, suppressed the (Na+, K+)-ATPase.
3.
- 1.1. The specific activity of Na-K ATPase was determined from the microsomal preparation of gills dissected from adult Macrobrachium rosenbergii.
- 2.2. Maximal ATPase activity was achieved at a substrate concentration of 0.5 mM ATP.
- 3.3. Optimal enzyme activity was obtained at pH of 7.5.
- 4.4. The Arrhenius plot of Na-K ATPase activity revealed a marked discontinuity at 30°C. “Mg” ATPase activity did not exhibit a marked discontinuity.
- 5.5. The Ea for Na-K ATPase and “Mg” ATPase was 14.6 kCal/mole and 9.31 kCal/mole respectively. Q10 values for Na-K ATPase was 2.34 and for “Mg” ATPase 1.65.
- 6.6. ATPase activity and gill homogenate protein concentration exhibited a linear relationship up to 130 μg protein/ml.
- 7.7. Na-K ATPase activity was inhibited by 10−3 M ouabain. It was equally inhibited by the removal of K+ from the reaction medium.
4.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1990,95(2):383-390
- 1.1. Homogenates of gills from the freshwater shrimp M. amazonicum exhibit the following ATPase activities: (i) a basal, Mg2+-dependent ATPase; (ii) an ouabain-sensitive, Na+ + K+-stimulated ATPase; (iii) an ouabain-insensitive, Na+-stimulated ATPase; and (iv) an ouabain-insensitive, K+-stimulated ATPase.
- 2.2. K+ suppresses the Na+-stimulated ATPase activity in a mixed-type kind of inhibition, whereas Na+ does not exert any noticeable effect on the K+-stimulated ATPase activity.
- 3.3. The Na+- and the K+-stimulated ATPase activities are totally inhibited by 5 mM ethacrynic acid in the incubation medium.
- 4.4. The Na+- and the K+-stimulated ATPase activities are not expressions of the activation of a Ca-ATPase.
- 5.5. The possible localization and roles of the described ATPases within the gill epithelium are briefly discussed and evaluated.
5.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1988,89(2):473-478
- 1.1. Cadmium (Cd) and zinc (Zn) were inhibitory to calcium uptake by isolated gills of Fundulus heteroclitus in vitro. The metals appeared to act by displacing Ca2+ ions from protein carriers involved in facilitated diffusion.
- 2.2. In saltwater fish, transport of calcium across the serosal membrane of gill chloride cells is partly energy dependent and is likely mediated by Ca2+-ATPase. However, much of the calcium transport through the gill epithelium appears to occur by passive processes.
- 3.3. Cd (10−5M—10−3M) and Zn (10−7M—10−3 M) inhibited calcium uptake by isolated scale patches incubated in a physiological saline.
- 4.4. Cyanide, oubain, and quercetin treatment of scale patches produced results similar to those of the Cd and Zn treatments suggesting that metal-induced inhibition of ATPases may be responsible for reduced calcium transport by scale osteoblasts.
6.
- 1.1. Rainbow trout were acclimated to salt water (1.5, 2.0 or 3.0%, which means 40, 60 or 85% concentrated sea-water) and the electrolyte, glucose and cortisol concentrations of the plasma as well as the extra- and intracellular muscle space, the muscle electrolyte concentrations and the ATPase activity were analysed.
- 2.2. Plasma osmolality, Na+, Ca2+ and Mg2+ concentrations of the plasma had a maximum at 24 hr after the start of acclimation when acclimated to 3.0% salt water. Plasma osmolality, Na+ and Mg2+ concentrations were significantly higher during the whole acclimation time when exposed to 3.0% salt water.
- 3.3. Variations and regulations of ECS and ICS were clearly demonstrated. The intracellular electrolyte concentrations were also maximal at 24 hr.
- 4.4. The plasma glucose level was just slightly elevated, but the cortisol level clearly indicated a stress response at 24 hr.
- 5.5. The activity of gill Na-K-ATPase increased during the acclimation time.
- 6.6. The regulatory processes in trout during acclimation to salt water are compared with those occurring in tilapia and carp.
7.
《The International journal of biochemistry》1990,22(10):1165-1170
- 1.1. As reported previously (Robinson, 1988) the Ca2+-induced self-association reaction of the protein hyalin, purified from the sea urchin extraembryonic hyaline layer, was modulated by both Mg2+ and NaCl.
- 2.2. In the presence of 400 mM NaCl the apparent dissociation constant (Ca2+) decreased five-fold from 4.8 ± 1.1 mM in the absence to 0.9 ± 0.5 mM in the presence of 20 mM Mg2+.
- 3.3. The potentiating effect of Mg2+ occurred with an apparent dissociation constant (Mg2+) of 4.6 ± 0.5mM.
- 4.4. In the absence of Ca2+ or NaCl hyalin dissociated from isolated hyaline layers indicating that the behavior of hyalin within the layer is predictable from results obtained with the purified protein.
8.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1993,104(3):719-728
- 1.1. Two components of Ca2+-Mg2+-ATPase are observed in kidneys of G. mirabilis. The high-affinity component has a K0.5Ca of 0.23μM; the low-affinity activity K0.5Ca is 90–110μM. The high-affinity activity requires Mg2+, displays Michaelis-Menten kinetics, has peak activity at 1.2 μM Ca2+, and is insensitive to ouabain and Na+ azide.
- 2.2. In subcellular fractions, the high-affinity component segregates with Na+-K+-ATPase and is localized predominantly in BLM. The low-affinity component is broadly distributed among membranous organelles, including brush border, and may be equivalent to alkaline phosphatase.
- 3.3. Specific activity of the high-affinity Ca2+-Mg2+-ATPase is modestly increased following adaptation of fish to FW, but total renal high-affinity activity is greatest in the hypertrophied kidneys of FW-adapted fish and is least in kidneys of fish adapted to 200% SW.
- 4.4. High-affinity Ca2+-Mg2+-ATPase may be associated with active Ca2+ transport or with regulation of intracellular Ca2+ concentration of tubular cells.
9.
《The International journal of biochemistry》1992,24(10):1657-1660
- 1.1. A thermostable orthophosphoric monoester phosphohydrolase (EC 3.1.3.1) from Thermus sp strain Rt41A has been purified 400-fold to give a specific activity of 25 U/mg at 60°C in IM diethanolamine (pH 11.1).
- 2.2. The enzyme has a Mr of 160,000 and is trimeric.
- 3.3. The half-life of the enzyme is 5 min at 85°C.
- 4.4. The enzyme has a wide specificity for a number of phosphate monoesters.
- 5.5. The Hm of the enzyme is pH dependent, so the pH optimum of the enzyme is affected by the substrate concentration.
- 6.6. The enzyme is inhibited 50% by 20 mM Ca2+ or Mg2+.
- 7.7. The Ki for phosphate, EDTA-di sodium salt and arsenate (in 1 M diethanolamine, pH 11.1) is approx 1.2, 1.6 and 4mM respectively.
- 8.8. Urea (200 mM) is not inhibitory.
10.
《The International journal of biochemistry》1993,25(1):7-12
- 1.1. Alkaline p-nitrophenylphosphate phosphatase of Halobacterium halobiium, either purified or in crude extracts, was progressively inactivated by treatment with several metal chelators.
- 2.2. The activity of treated crude extracts was fully restored in the presence of 25–50 μM Mn2+ or 1 mM Co2+, and partially restored in the presence of 1 mM Cd2+.
- 3.3. Zn2+ ions, as well as other divalent cations tested, were without effect.
- 4.4. In the presence of a saturating concentration of Mn2+, but not Co2+ or Cd2+, the activity of the metal-depleted enzyme reached values well over the native control activity.
- 5.5. Activation of the metal-depleted enzyme by Mn2+ showed cooperative kinetics, whereas activation by Co2+ showed Lineweaver-Burk kinetics.
- 6.6. The results suggest that the enzyme contains two different types of metal-binding sites: essential site(s), occupied by endogenous Mn2+ ions, and regulatory site(s), that can be occupied by exogenous Mn2+ with an activating effect.
11.
《The International journal of biochemistry》1991,23(9):881-887
- 1.1. As reported previously (Hopper and Robinson, 1990; Int. J. Biochem. 22, 1165–1170) the sea urchin extraembryonic coat protein hyalin undergoes a Ca2+-induced self-association into an insoluble gel (gelation) in the presence of Mg2+ and/or NaCl.
- 2.2. A 275 kDa peptide fragment, generated by limited tryptic digestion of hyalin, binds Ca2++ but does not undergo gelation in the presence of Ca2+, Mg2+ and NaCl.
- 3.3. Comparisons between the capacities of hyalin and the 275 kDa peptide fragment to bind Ca2+ indicate that the latter binds 88% less Ca2+ than hyalin.
- 4.4. However, the presence of Ca2+ alone, at a concentration of 5 mM, protects the 275 kDa peptide fragment from further digestion by trypsin mimicking the effect of this cation in protecting hyalin.
- 5.5. Gel exclusion Chromatographie analyses of the 275 kDa peptide fragment, both in the presence and absence of 5 mM Ca2+, indicate that this cation does induce self-association of the fragment.
- 6.6. These results provide information on the organization of the functional domains on hyalin which are required for gel formation.
12.
《Comparative biochemistry and physiology. B, Comparative biochemistry》1993,104(3):547-550
- 1.1. Crude extract of the whole digestive tract from the brown shrimp (P. californiensis) was investigated for digestive amylase activity.
- 2.2. Considerable amylase activity was found at pH 6.5–8.0, with optimum pH at around 7.5.
- 3.3. Optimum temperature was found between 30–40°C, similar to amylases from other crustaceans.
- 4.4. Amylase activity was highly halotolerant, having 50% maximum activity at 3 M NaCl.
- 5.5. Maximum amylase activity was found at 0.01 M NaCl.
- 6.6. Amylase activity was partially inhibited by the divalent ions Hg2+, Zn2+, Cu2+ and Cr2+.
- 7.7. Mg2+ and Ca2+ ions seemed to enhance amylase activity.
13.
《Comparative biochemistry and physiology. A, Comparative physiology》1984,77(4):673-678
- 1.1. Specific activity and kinetic characteristics of the (Na+ + K+)ATPase have been investigated in the gill epithelium of the hyper-hypoosmoregulator crab Uca minax.
- 2.2. (Na+ +K+)ATPase activity is shown to be at least three times higher in the posterior gills.
- 3.3. The kinetic study supports the hypothesis of the existence of two different (Na+ + K+)ATPases: the enzyme activity in the posterior gills could be involved in the transepithelial transport of Na+ while the activity of the anterior gills could be responsible for the intracellular regulation of Na+ and K+.
- 4.4. Significant and specific changes in (Na+ +K+)ATPase activity occur upon acclimation to media of various salinities.
14.
《The International journal of biochemistry》1991,23(10):991-995
- 1.1. Purified ostrich (Struthio camelus) liver fructose-1,6-bisphosphatase exhibited an absolute requirement for Mg2+.
- 2.2. The enzyme catalyzed the hydrolysis of fructose-1,6-bisphosphate, sedoheptulose-l,7-bisphosphate and ribulose-l,5-bisphosphate.
- 3.3. S0.5 for substrate was 1.4 μM.
- 4.4. AMP was a potent non-competitive inhibitor with respect to substrate (Ki of 25 μM).
- 5.5. Fructose-2,6-bisphosphate was a potent competitive inhibitor of the enzyme (Ki of 4.8 μM).
15.
《The International journal of biochemistry》1993,25(8):1115-1120
- 1.1. The inhibition kinetics of sheep brain butyrylcholinesterase (BChE) (acylcholine acylhydrolase, EC 3.1.1.8) by Cd2+ and Zn2+ has been studied.
- 2.2. Ks has been determined as 0.14mM. Cd2+ and Zn2+ were the hyperbolic mixed-type inhibitors of BChE. Ca2+ and Mg2+ had no effect on the enzyme activity in the experimental conditions.
- 3.3. But when the enzyme was inhibited by 0.1 mM Cd2+ or Zn2+, Ca2+ and Mg2+ reactivated the inhibited form of BChE.
16.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1988,89(2):503-505
- 1.1. Microelectrodes have been used to measure K+ activities and electrical potential differences between the perivitelline fluid (pvf) of the eggs of pike (Esox lucius) and surrounding water in a range of pH, calcium and aluminium concentrations.
- 2.2. Potential differences between pvf and water are decreased by Ca2+ (10−3 M) while Al3+ (18 × 10−6 M) reverses the polarity of the potential difference.
- 3.3. K+ activities in the pvf of eggs in 10−4M KCl + 10−5M NaCl are decreased by Ca2+(10−3 M).
- 4.4. The results are discussed with reference to ion-exchange theory and chorion permeability.
17.
《Comparative biochemistry and physiology. A, Comparative physiology》1993,104(2):309-312
- 1.1. The objective of the present study was to determine the effect of age and taurine on chick B cell calcium uptake and membrane (Ca2+ + Mg2+)-ATPase activity in 1–4-week-old chicks.
- 2.2. The calcium uptake rate decreased with age (P < 0.05) and was further decreased by taurine (P < 0.05).
- 3.3. (Ca2+ + Mg2+)-ATPase activity increased with age (P < 0.05) and was stimulated by taurine (P < 0.05).
- 4.4. The data demonstrate that the flux of calcium across the B-cell membrane changes during early post-hatch development, and that taurine regulates both the influx and efflux of calcium in chick B-cells.
18.
《The International journal of biochemistry》1993,25(5):641-652
- 1.1. A subcellular fractionation procedure for bovine adrenal glands was designed with the aim to study the biochemical properties of Ca2+ stores in chromaffin cells.
- 2.2. The thapsigargin-sensitive compartment of Ca2+ stores was found to be highly enriched in a light microsomal fraction (LMF) on a 15–30% linear sucrose gradient, and was found to be essentially devoid of contamination by plasma, mitochondrial or secretory granule membranes.
- 3.3. A Ca2+-pumping ATPase was identified in this LMF as a 97 kDa protein forming an acid-stable, Ca2+-dependent, thapsigargin-sensitive phosphorylated intermediate upon incubation with [γ-32P]ATP, suggesting this protein to represent a SERCA-3 isoform of Ca2+ ATPases.
- 4.4. A major 162 kDa protein, previously demonstrated in the isolated chromaffin cells, was enriched in the LMF, distributing on sucrose gradients in parallel with the thapsigargin-sensitive Ca2+ uptake.
- 5.5. LMF appears to represent a part of the thapsigargin-sensitive Ca2+ store of chromaffin cells, and should be useful for further studies of the store properties at the subcellular and molecular level.
19.
《Comparative biochemistry and physiology. A, Comparative physiology》1986,83(3):503-505
- 1.1. The shell side of the mantle of Achatina fulica is several millivolts positive to the blood side in vitro.
- 2.2. The electrical potential does not depend on Na+, Ca2+, Mg2+, K+ or HCO3− but requires the presence of chloride on the shell side.
- 3.3. The potential difference and short-circuit current ranged from 3.0 to 30.0 mV and 15.0 to 75 μA/cm2 with averages at 10m V and 50 μA/cm2 respectively.
- 4.4. The electrical gradient is reduced by 2,4-dinitrophenol, thiocyanate and furosemide but not by ouabain, CO2 or acetozolamide.
- 5.5. It is suggested that the nature and mechanism of electrogenesis in Achatina parallels that of the Helix mantle.
20.
《The International journal of biochemistry》1990,22(4):329-333
- 1.1. Ca2+ uptake, Ca2+-dependent ATPase activity and halothane-induced Ca2+ release from the heavy sarcoplasmic reticulum fraction of muscle from malignant hyperthermia susceptible individuals are similar to those of normal human muscle.
- 2.2. Ca2+-induced Ca2+ release from the diseased muscle was increased by 13%.