scholarly journals Water-soluble enzyme-polymer grafts: Thermal stabilization of glucose oxidase

1973 ◽  
Vol 15 (5) ◽  
pp. 1011-1016 ◽  
Author(s):  
H. F. Hixson
Keyword(s):  
Glucose Oxidase ◽  
Thermal Stabilization ◽  
Water Soluble ◽  
Soluble Enzyme

scholarly journals The activity of the intrinsically water-soluble enzyme ADAMTS13 correlates with the membrane state when bound to a phospholipid bilayer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrej Kamenac ◽  
Tobias Obser ◽  
Achim Wixforth ◽  
Matthias F. Schneider ◽  
Christoph Westerhausen
Keyword(s):  
Phase Transition ◽  
Acyl Chain ◽  
Water Soluble ◽  
Main Phase ◽  
Phospholipid Bilayer ◽  
Alternative Theory ◽  
Soluble Enzyme ◽  
Arrhenius Behavior ◽  
Activity Measurements ◽  
Gibb’S Free Energy

AbstractMembrane-associated enzymes have been found to behave differently qualitatively and quantitatively in terms of activity. These findings were highly debated in the 1970s and many general correlations and reaction specific models have been proposed, reviewed, and discarded. However, new biological applications brought up the need for clarification and elucidation. To address literature shortcomings, we chose the intrinsically water-soluble enzyme a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) and large unilamellar vesicles with a relative broad phase transition. We here present activity measurements of ADAMTS13 in the freely dissolved state and the membrane associated state for phosphocholine lipids with different acyl-chain lengths (13:0, 14:0 and 15:0) and thus main phase transition temperatures. While the freely dissolved enzyme shows a simple Arrhenius behavior, the activity of membrane associated ADAMTS13 in addition shows a peak. This peak temperature correlates with the main phase transition temperature of the used lipids. These findings support an alternative theory of catalysis. This theory predicts a correlation of the membrane associated activity and the heat capacity, as both are susceptibilities of the same surface Gibb’s free energy, since the enzyme is attached to the membrane.

scholarly journals Sulphation as a metabolic pathway for oestradiol in the sea urchin Strongylocentrotus franciscanus

1967 ◽  
Vol 102 (3) ◽  
pp. 898-904 ◽  
Author(s):  
John E. Creange ◽  
Clara M. Szego
Keyword(s):  
Sea Urchin ◽  
Metabolic Pathway ◽  
Enzyme System ◽  
Water Soluble ◽  
Soluble Form ◽  
Soluble Enzyme ◽  
Aerobic Incubation ◽  
Strongylocentrotus Franciscanus ◽  
Rapid Formation

1. Aerobic incubation of [(14)C]oestradiol, in the presence of surviving gut tissue of the sea urchin Strongylocentrotus franciscanus, or a soluble enzyme system prepared therefrom, resulted in rapid formation of a water-soluble metabolite, identified as oestradiol 3-sulphate. 2. No evidence was obtained for the formation of other metabolic derivatives by the urchin-gut enzymes, or for the presence of the sulphating capacity in any other tissues of the organism under the conditions used. 3. The data are consistent with the possibility that oestradiol, previously detected in the gonads, is synthesized therein and excreted in a conjugated, highly water-soluble form via the gut.

scholarly journals Thermal stabilization of glucose oxidase and glucoamylase by physical entrapment

1981 ◽  
Vol 193 (2) ◽  
pp. 389-394 ◽  
Author(s):  
V Basaveswara Rao ◽  
N V S Sastri ◽  
P V Subba Rao
Keyword(s):  
Glucose Oxidase ◽  
Thermal Stabilization ◽  
Polyacrylamide Gels ◽  
Physical Entrapment ◽  
The Individual

Physical entrapment was used as an approach to achieve thermal stabilization of enzymes. The t 1/2 values for the thermoinactivation of glucose oxidase and glucoamylase were increased several-fold by their entrapment in polyacrylamide gels. In polyacrylate gels the individual enzymes behaved differently, probably owing to microenvironmental effects arising by the polyelectrolyte nature of the carrier.

scholarly journals BIOSYNTHESIS OF FATTY ACIDS BY CELL-FREE OR WATER-SOLUBLE ENZYME SYSTEMS

1952 ◽  
Vol 199 (1) ◽  
pp. 421-431 ◽  
Author(s):  
Roscoe O. Brady ◽  
Samuel Gurin ◽  
With the technical assistance of Jessie Van Baalen
Keyword(s):  
Fatty Acids ◽  
Water Soluble ◽  
Soluble Enzyme ◽  
Enzyme Systems

scholarly journals Phosphatidylinositol phosphodiesterase in higher plants

1980 ◽  
Vol 192 (1) ◽  
pp. 279-283 ◽  
Author(s):  
R F Irvine ◽  
A J Letcher ◽  
R M C Dawson
Keyword(s):  
Phosphatidic Acid ◽  
Phospholipase C ◽  
Higher Plants ◽  
Water Soluble ◽  
Apium Graveolens ◽  
Soluble Enzyme ◽  
Ph Optimum ◽  
Bivalent Cation ◽  
Detectable Activity ◽  
Ph Range

1. The lower regions of the stem of celery (Apium graveolens L.) contain a soluble enzyme that hydrolyses phosphatidylinositol. 2. The lipoidal product of hydrolysis is diacylglycerol, and the water-soluble products are 1:2-cyclic phosphoinositol and phosphoinositol in the approximate proportions of 60% and 40% respectively: this indicates that a phosphodiesterase (phospholipase C-like) activity is cleaving the phosphatidylinositol. 3. The enzyme requires a bivalent cation, Ca2+ being the most effective activator. 4. The enzyme has a pH optimum, depending on conditions of assay, of pH 5.9-6.6 and in this pH range shows no detectable activity against phosphatidylcholine or phosphatidylethanolamine. 5. The activity is stimulated by phosphatidic acid and slightly inhibited (30% at concentrations equimolar with phosphatidylinositol) by phosphatidylcholine. 6. The phosphodiesterase was also detected (but not quantified) in the tips of the flowers in cauliflowers, in outer leaves of onion and in the elongating stem of daffodils. 7. The enzyme's properties are compared with equivalent mammalian enzymes, and its possible role in the catabolism of phosphatidylinositol in higher plants is discussed.

Iron Dienylphosphate Tricarbonyl Complexes as Water-Soluble Enzyme-Triggered CO-Releasing Molecules (ET-CORMs)

2012 ◽  
Vol 31 (16) ◽  
pp. 5800-5809 ◽  
Author(s):  
Steffen Romanski ◽  
Hannelore Rücker ◽  
Eleni Stamellou ◽  
Miguel Guttentag ◽  
Jörg-Martin Neudörfl ◽  
...  
Keyword(s):  
Water Soluble ◽  
Soluble Enzyme

Application of a New Peroxide Indicator Reaction to the Specific, Automated Determination of Glucose with Glucose Oxidase

1972 ◽  
Vol 18 (9) ◽  
pp. 943-950 ◽  
Author(s):  
Nathan Gochman ◽  
Joan M Schmitz
Keyword(s):  
Glucose Oxidase ◽  
Biological Fluids ◽  
Water Soluble ◽  
Colorimetric Determination ◽  
Indicator Reaction ◽  
Reducing Substances ◽  
Alkaline Ferricyanide ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Automated Methods

Abstract We describe an automated, colorimetric determination of glucose in biological fluids that combines the specificity of glucose oxidase and of a new peroxide indicator reaction. In the presence of peroxidase, 3-methyl-2-benzothiazolinone hydrazone oxidatively couples with N,N-dimethylaniline to form a stable, intensely colored, water-soluble indamine dye, the concentration of which is proportional to that of the third reactant, hydrogen peroxide. This reaction, used earlier to determine uric acid [Clin. Chem. 17, 1154 (1971)], is substantially less affected by negative interference of reducing substances than are previously described peroxide indicators. Results from use of AutoAnalyzers I and II and this method were compared with those from a manual spectrophotometric hexokinase/glucose-6-phosphate dehydrogenase procedure, and showed good correlation for specimens from patients. The automated methods are suitable for measuring glucose in serum, plasma from fluoride-or iodoacetate-preserved blood, urine (without ion-exchange pretreatment), or cerebrospinal fluid. They eliminate the problem of falsely high results caused by medication or reducing metabolites associated with uremia, in methods in which alkaline ferricyanide or copper—neocuproine is used.

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