scholarly journals Enzyme Reactivation

2020 ◽  
Author(s):  
Keyword(s):  
Enzyme Reactivation

scholarly journals Kinetic analysis of regeneration by dilution of a covalently modified protein

1990 ◽  
Vol 268 (3) ◽  
pp. 669-670 ◽  
Author(s):  
E T Rakitzis
Keyword(s):  
Reaction Time ◽  
Rate Constants ◽  
Constant Term ◽  
Covalent Modification ◽  
Regeneration Rate ◽  
Modifying Agent ◽  
Reaction Rate Constants ◽  
Enzyme Reactivation ◽  
Microscopic Reaction ◽  
Single Exponential

An analysis of regeneration by dilution of a covalently modified protein is presented. It is shown that, when protein regeneration is realized through the intermediacy of a protein-modifying agent adsorptive complex, the reaction is described by a summation of two exponential functions of reaction time plus a constant-term equation. The conditions whereby this equation reduces to a single-exponential equation are delineated. It is shown that, when protein regeneration is described by a single-exponential function of reaction time, the first-order protein-regeneration rate constant is a function of modifying-agent concentration and also of the microscopic reaction rate constants. Accordingly, the protein-modifying agent dissociation constant (Ki), as well as the protein-covalent-modification and -regeneration, rate constants (k+2 and K-2), may be determined by an analysis of dilution-induced protein-regeneration (or enzyme-reactivation) data obtained at different dilutions of the covalently modified protein-modifying agent preparation.

scholarly journals In Vitro Evaluation of Neutral Aryloximes as Reactivators for Electrophorus eel Acetylcholinesterase Inhibited by Paraoxon

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 583 ◽  
Author(s):  
Daniel Kitagawa ◽  
Samir Cavalcante ◽  
Reuel de Paula ◽  
Rafael Rodrigues ◽  
Leandro Bernardo ◽  
...  
Keyword(s):  
Organophosphorus Pesticides ◽  
Structural Factors ◽  
Poor Countries ◽  
Lead Compounds ◽  
Irreversible Inhibitors ◽  
Sar Studies ◽  
Pyridinium Oximes ◽  
The Central Nervous System ◽  
Enzyme Reactivation

Casualties caused by organophosphorus pesticides are a burden for health systems in developing and poor countries. Such compounds are potent acetylcholinesterase irreversible inhibitors, and share the toxic profile with nerve agents. Pyridinium oximes are the only clinically available antidotes against poisoning by these substances, but their poor penetration into the blood-brain barrier hampers the efficient enzyme reactivation at the central nervous system. In searching for structural factors that may be explored in future SAR studies, we evaluated neutral aryloximes as reactivators for paraoxon-inhibited Electrophorus eel acetylcholinesterase. Our findings may result into lead compounds, useful for development of more active compounds for emergencies and supportive care.

scholarly journals Enzyme Reactivation by Hydrogen Peroxide in Heme-based Tryptophan Dioxygenase

2011 ◽  
Vol 286 (30) ◽  
pp. 26541-26554 ◽  
Author(s):  
Rong Fu ◽  
Rupal Gupta ◽  
Jiafeng Geng ◽  
Kednerlin Dornevil ◽  
Siming Wang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Tryptophan Dioxygenase ◽  
Enzyme Reactivation

scholarly journals Comparative effects of wheat bran and barley husk on nutrient utilization in rats

1986 ◽  
Vol 56 (1) ◽  
pp. 269-280 ◽  
Author(s):  
Carmen M. Donangelo ◽  
B. O. Eggum
Keyword(s):  
Wheat Bran ◽  
Nitrogen Concentration ◽  
Nutrient Utilization ◽  
Molar Ratio ◽  
Control Group ◽  
Mineral Concentration ◽  
Barley Husk ◽  
Negative Effect ◽  
Enzyme Reactivation ◽  
Old Rats

1. The present work was undertaken to study comparatively the effect on mineral availability in rats of wheat bran and barley husk when supplying the same amount of dietary fibre (DF). The experiment involved a total of nine dietary treatments including a control group and two series of four groups with increasing amounts of fibre from the two sources (total DF ranging from 42 to 117 gsol;kg dry matter (DM)). Dietary nitrogen concentration was kept constant at 15 g N/kg DM. Zinc concentration of the diets was adjusted to the level provided by the diet with the highest wheat-bran content (21 mg/kg DM) using zinc sulphate. Other minerals were not adjusted.2. Two experiments were performed. In Expt 1 the diets were given to 5-week-old rats during 9 d and apparent absorptions of Zn, calcium and phosphorus and the femur concentrations of Zn, Ca and P were measured. In Expt 2 the diets were given to 9-week-old rats during 12 d. Mineral concentration in femur and total and albumin-bound plasma Zn and availability of plasma Zn for enzyme reactivation were measured.3. In the younger animals, wheat bran depressed significantly the absorption of Zn when providing 40 g DF/kg DM and absorbtion of Ca when providing 80g DF/kg DM. Barley husk depressed significantly both the absorption of Zn and Ca already at 20 g DF/kg DM. Both fibre sources had a more negative effect on Zn than on Ca absorption. Only barley husk had a small negative effect on absorption of P. Phytate did not appear as a major factor affecting mineral absorption in barley husk. All diets containing barley husk had a very low molar ratio, phytate:Zn.4. The age orthe animals influenced the utilization of dietary minerals using femur Concentration as a criterion, particularly in the case of Zn. In the younger animals the decrease in femur Zn with fibre correlated with apparent Zn absorption both with wheat bran (R2 0.986, P < 0.01) and with barley husk (R2 0.996, P < 0.01). In the older animals femur Zn did not change significantly with fibre.5. In the older animals, plasma Zn, albumin-bound plasma Zn and availability of plasma Zn for enzyme reactivation were lowest with the highest addition of wheat bran.

Mechanism-based inactivation of chloroperoxidase with terminal olefins. Identification of an intermediate in the spontaneous enzyme reactivation

1995 ◽  
Vol 59 (2-3) ◽  
pp. 473
Author(s):  
Annette F. Dexter ◽  
Yao-Min Xia ◽  
Peter G. Debrunner ◽  
Joachim D. Mueller ◽  
Lowell P. Hager
Keyword(s):  
Enzyme Reactivation ◽  
Terminal Olefins

scholarly journals Ubiquitination-Induced Conformational Change within the Deiodinase Dimer Is a Switch Regulating Enzyme Activity

2007 ◽  
Vol 27 (13) ◽  
pp. 4774-4783 ◽  
Author(s):  
G. D. Vivek Sagar ◽  
Balázs Gereben ◽  
Isabelle Callebaut ◽  
Jean-Paul Mornon ◽  
Anikó Zeöld ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Conformational Change ◽  
Regulatory Protein ◽  
Tight Control ◽  
Enzymatic Function ◽  
Cytosolic Domains ◽  
Enzyme Reactivation ◽  
Interacting Surfaces

ABSTRACT Ubiquitination is a critical posttranslational regulator of protein stability and/or subcellular localization. Here we show that ubiquitination can also regulate proteins by transiently inactivating enzymatic function through conformational change in a dimeric enzyme, which can be reversed upon deubiquitination. Our model system is the thyroid hormone-activating type 2 deiodinase (D2), an endoplasmic reticulum-resident type 1 integral membrane enzyme. D2 exists as a homodimer maintained by interacting surfaces at its transmembrane and globular cytosolic domains. The D2 dimer associates with the Hedgehog-inducible ubiquitin ligase WSB-1, the ubiquitin conjugase UBC-7, and VDU-1, a D2-specific deubiquitinase. Upon binding of T4, its natural substrate, D2 is ubiquitinated, which inactivates the enzyme by interfering with D2's globular interacting surfaces that are critical for dimerization and catalytic activity. This state of transient inactivity and change in dimer conformation persists until deubiquitination. The continuous association of D2 with this regulatory protein complex supports rapid cycles of deiodination, conjugation to ubiquitin, and enzyme reactivation by deubiquitination, allowing tight control of thyroid hormone action.

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