scholarly journals Characterization of cuckoo-pint (Arum maculatum) mitochondrial adenosine triphosphatases

1986 ◽  
Vol 233 (3) ◽  
pp. 839-844 ◽  
Author(s):  
P P J Dunn ◽  
A R Slabas ◽  
A L Moore
Keyword(s):  
Adenosine Triphosphatase ◽  
Kinetic Properties ◽  
Ph Profile ◽  
Enzyme Preparations ◽  
Adenosine Triphosphatases ◽  
Membrane Bound ◽  
Cold Stability ◽  
Arum Maculatum ◽  
Guanosine Triphosphatase ◽  
Soluble Enzymes

The catalytic properties of cuckoo-pint (Arum maculatum) mitochondrial adenosine triphosphatase have been analysed. The pH profile, effect of inhibitors, cold-stability and substrate specificity are characteristic of mitochondrial adenosine triphosphatases, although a high guanosine triphosphatase activity does appear to be restricted to plant mitochondrial adenosine triphosphatases. The kinetic properties of nucleoside 5′-triphosphate hydrolysis by membrane-bound and soluble enzymes have been studied by means of double-reciprocal plots. These plots were linear in the absence of an activating anion, which may indicate that the catalytic and/or regulatory mechanism of Arum maculatum adenosine triphosphatase is different from that of other enzyme preparations. It is suggested that the differences in subunit composition of plant and mammalian adenosine triphosphatases reported previously [Dunn, Slabas & Moore (1985) Biochem. J. 225, 821-824] are structurally, rather than functionally, significant.

Effects of Ethylene, Carbon Dioxide, and Ethylene – Carbon Dioxide Mixtures on the Activities of "Membrane-Containing" and "Highly Purified" Preparations of Adenosine Triphosphatase from Pea-Cotyledon Mitochondria

1974 ◽  
Vol 52 (12) ◽  
pp. 1091-1096 ◽  
Author(s):  
S. S. Malhotra ◽  
Mary Spencer
Keyword(s):  
Carbon Dioxide ◽  
Adenosine Triphosphatase ◽  
Direct Action ◽  
Gas Mixture ◽  
Mitochondrial Atpase ◽  
Enzyme Preparations ◽  
Membrane Bound

From pea-cotyledon mitochondria two types of adenosine triphosphatase (ATP phosphohydrolase) were prepared, "membrane-bound" and "highly purified." Activities of both enzyme preparations were dependent on Mg2+ and were stimulated by Na+ and K+. Ethylene had no effect on the activity of either the "membrane-bound" or the "highly purified" enzyme. Ethylene – carbon dioxide – air mixtures stimulated the activity of the "membrane-bound" but not the "highly purified" ATPase, when Na+ and K+ were present. When these ions were absent, the gas mixture greatly increased the activities of both enzyme preparations. The work shows a direct action of ethylene on an enzyme (mitochondrial ATPase), its dependence on the presence of certain levels of CO2, and the augmentation of the ethylene–CO2 effects by the presence of phospholipids.

scholarly journals PROBLEMS ASSOCIATED WITH THE DEMONSTRATION BY LEAD METHODS OF ADENOSINE TRIPHOSPHATASE ACTIVITY IN RESIDENT PERITONEAL MACROPHAGES AND EXUDATE MONOCYTES OF THE GUINEA PIG

1973 ◽  
Vol 21 (5) ◽  
pp. 488-498 ◽  
Author(s):  
R. E. POELMANN ◽  
W. T. DAEMS ◽  
E. J. VAN LOHUIZEN
Keyword(s):  
Plasma Membrane ◽  
Guinea Pig ◽  
Microscopic Study ◽  
Heterogeneous Nucleation ◽  
Adenosine Triphosphatase ◽  
Peritoneal Macrophages ◽  
Electron Microscopic ◽  
Adenosine Triphosphatase Activity ◽  
Eosinophilic Granulocytes ◽  
Membrane Bound

This cytochemical and electron microscopic study on peritoneal macrophages of the guinea pig has raised doubts concerning the validity of lead methods for the demonstration of plasma membrane-bound adenosine triphosphatase activity. The problems encountered are inherent in the use of lead ions as a capture reagent. The nonenzymatically formed precipitates reflect sites of heterogeneous nucleation specific for certain kinds of cells, e.g., resident peritoneal macrophages, eosinophilic granulocytes and, to a lesser degree, exudate monocytes. This type of precipitation is also catalyzed on the surface of nonbiologic matrices such as latex particles. Enzymatic processes may well occur, but they cannot be distinguished from nonenzymatic processes.

Characterization of the Metamitron Deaminating Enzyme Activity from Sugar Beet ( Beta vulgaris L.) Leaves

1979 ◽  
Vol 34 (11) ◽  
pp. 948-950 ◽  
Author(s):  
Carl Fedtke ◽  
Robert R. Schmidt
Keyword(s):  
Cytochrome C ◽  
Sugar Beet ◽  
Electron Donor ◽  
Nitrogen Atmosphere ◽  
Enzyme Preparations ◽  
Reducing Conditions ◽  
Trade Name ◽  
Membrane Bound

Abstract The enzymatic activity from sugar beet leaves which is responsible for the detoxification of the herbicide metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1, 2, 4-triazin-5-one, trade name Goltix®) has been characterized in vitro. The detoxification occurs by rapid deamination in vivo as well as in vitro. However, the deamination in vitro is only maximal under reducing conditions, i. e. with an electron donor and in a nitrogen atmosphere. The electron donor may be cystein, glutathione, dithionite or ascorbate. The enzymatic deamination further requires the addition of cytochrome c and a “supernatant factor”, which may be replaced by FMN, FAD or DCPIP. However, in the presence of FMN or DCPIP cytochrome c is not essential but only stimulatory. The partic­ulate as well as the soluble metamitron deaminating enzyme preparations obtained take up oxygen when supplied with cysteine and FMN. The particulate enzyme appears in the peroxysome-fraction. It is therefore suggested, that the enzymatic deamination of metamitron in sugar beet leaves is mediated by a proxisomal membrane bound electron transport system which alternatively may reduce oxygen or metamitron (deaminating).

scholarly journals Membrane isolation on polylysine-coated beads. Plasma membrane from HeLa cells.

1977 ◽  
Vol 75 (1) ◽  
pp. 119-134 ◽  
Author(s):  
C M Cohen ◽  
D I Kalish ◽  
B S Jacobson ◽  
D Branton
Keyword(s):  
Adenosine Triphosphatase ◽  
Wheat Germ ◽  
Plasma Membranes ◽  
Cell Attachment ◽  
Isolation Procedure ◽  
Chemical Analyses ◽  
Isolation Techniques ◽  
Cell Plasma ◽  
Membrane Bound ◽  
Membrane Isolation

HeLa cell plasma membranes have been purified after binding cells to polylysine-coated polyacrylamide beads. Cell attachment to beads and membrane recovery were maximal in a sucrose-acetate buffer, pH 5.0, at 25 degrees C. Measurements of ouabain-sensitive NaK-adenosine triphosphatase, membrane-bound 125I-wheat germ agglutinin, and chemical analyses showed that membranes on beads were of comparable or greater purity than membranes isolated by conventional methods. Because the isolation procedure is rapid (approximately 2.5 h), and produces membranes whose protoplasmic surfaces are fully exposed, it should be a useful supplement to standard isolation techniques.

scholarly journals Evaluation of optimal conditions for arginase activity in streptozotocin induced diabetic rats

2012 ◽  
Vol 50 (No. 2) ◽  
pp. 69-76 ◽  
Author(s):  
M. Erisir ◽  
E. Ercel ◽  
S. Yilmaz ◽  
S. Ozan
Keyword(s):  
Maximal Activity ◽  
Diabetic Rats ◽  
Arginase Activity ◽  
Female Rats ◽  
Kinetic Properties ◽  
Ph Profile ◽  
Optimum Ph ◽  
Liver And Kidney ◽  
And Control ◽  
Assay Conditions

The assay conditions needed to achieve maximal activity of liver and kidney arginase in diabetic and non-diabetic rats were investigated and compared. The physicochemical and kinetic properties of liver arginase in diabetic and control rats were very similar, those of kidney arginase were significantly different. It was found that preincubation temperature (68&deg;C), preincubation period (20 min), optimum pH (10.1) of liver arginase and K<sub>m</sub> (3.2) for its substrate, L-arginine, did not change in diabetic and non-diabetic rats. As a consequence of diabetes, the optimum Mn<sup>2+</sup> concentration for liver arginase only changed from 1 to 2 mM. Although the preincubation temperature and period for activation of kidney arginase in control rats was unnecessary, they were found to be 56&ordm;C and 12 min in diabetic rats. The pH profile of arginase in kidney of diabetic rats was different from that of control rats. The K<sub>m</sub> value (6.7) of arginase for L-arginine in kidney is unchanged in diabetes whereas a marked decrease in V<sub>max</sub> was found. Optimum Mn<sup>2+</sup> concentration (2 mM) for kidney arginase was unchanged in diabetes. The activity of arginase in liver of diabetic animals was higher 1.5 to 1.7 times than that of controls. Diabetes caused an about 53% decrease of arginase activity in kidney of female rats, 26% in that of males. These findings may suggest an idea that encoded arginases by separate gene loci may be affected differently by the pathological and hormonal status.

K depletion modifies the properties of Sch-28080-sensitive K-ATPase in rat collecting duct

1997 ◽  
Vol 272 (1) ◽  
pp. F124-F131 ◽  
Author(s):  
B. Buffin-Meyer ◽  
M. Younes-Ibrahim ◽  
C. Barlet-Bas ◽  
L. Cheval ◽  
S. Marsy ◽  
...  
Keyword(s):  
Collecting Duct ◽  
Rat Kidney ◽  
Lower Sensitivity ◽  
Kinetic Properties ◽  
Type I ◽  
Type Ii ◽  
Distribution Profile ◽  
Adenosine Triphosphatases ◽  
Collecting Ducts ◽  
K Depletion

Two distinct Sch-28080-sensitive K-adenosine triphosphatases (K-ATPases) were previously described in the rat nephron: a ouabain-resistant K-ATPase (type I) present in collecting ducts (CD) and a ouabain-sensitive from (type II) located in proximal tubules (PT) and thick ascending limbs (TAL). In K-depleted rats, K-ATPase activity is increased in CD, whereas it is reduced in PT and TAL. Because expression of colonic H-K-ATPase is restricted to the CD of K-depleted rats, we hypothesized that K-ATPase from the CD of K-depleted rats might be different from types I and II. Indeed, type III K-ATPase displays higher sensitivities to ouabain and to Sch-28080 than type II, a lower sensitivity to Sch-28080 than type I, and, conversely to types I and II, it can be stimulated by Na+. Pharmacological differences between types II and III K-ATPases were confirmed by [3H]ouabain binding experiments. Thus the rat kidney expresses three K-ATPases that differ by their pharmacological and kinetic properties, their distribution profile along the nephron and their behavior during K depletion.

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