A novel approach to study of action of water-insoluble inhibitors of enzymic reactions

Bi, Kurganov; Tsetlin, Larissa G.; Malakhova, E A; Chebotareva, Natalia A.; Ланкин, В. З.; Glebova, Galina D.; Berezovsky, Vladimir M.; Levashov, Andrey V.; Martínek, Karel

doi:10.1016/0165-022x(85)90053-3

Cited by 32 publications

(11 citation statements)

References 5 publications

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“…In line with the finding that profiles for kcat versus coo can be bell-shaped, there is an interesting hypothesis that suggests that, at the optimum coo, the protein dimensions match those of the waterpool of the reverse micelle [106,[140][141][142][143]. In support of this hypothesis, data on a dozen different enzymes have been presented where the optimum wo correlates, with some exceptions, with the molecular mass of the protein [2,48].…”

Section: Superactivity Of Enzymes In Reverse Micellesmentioning

confidence: 68%

Kinetic models in reverse micelles

Bru

Sánchez‐Ferrer

García-Carmona

1995

Biochemical Journal

102

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Section: Superactivity Of Enzymes In Reverse Micellesmentioning

confidence: 68%

Kinetic models in reverse micelles

Bru

Sánchez‐Ferrer

García-Carmona

1995

Biochemical Journal

102

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“…the data in [255] and [256], respectively. The coincidence of the optimal diameter of the micelle inner cavity with the molecular size of the entrapped enzyme was observed for cc-chymotrypsin [225, 2471, peroxidase [253] and lipoxygenase [257].…”

Section: Effects Of Water Contentmentioning

confidence: 98%

“…From [257] layer of a reversed micelle and, therefore, can come into contact with the entrapped enzyme. The interaction of lipoxygenase with 2',3',4,5'-tetrabenzoyl-5-acetyl-l,5-dihydroriboflavin (an analoque of vitamin B,) seems to occur in this way [257]. The latter compound has no effect on the catalytic activity of lipoxygenase in aqueous solution (up to the limit of its solubility of about 1 pM) The inhibition of the enzyme, entrapped in AOT-reversed micelles in octane, depends to a great extent on the degree of hydration of the micelles (Fig.…”

Section: Changes In Substrate Specijicity Of Solubilized Enzymesmentioning

confidence: 99%

Micellar enzymology

Martínek

Levashov

Klyachko

et al. 1986

European Journal of Biochemistry

Self Cite

548

248

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Experimental approaches to modelling the enzymatic function of biological membranes are discussed. Emphasis is given to pseudohomogeneous systems such as proteolipid complexes and enzymes in organic solvents; the latter are solubilized with phospholipids or synthetic surfactants. Methods for producing and studying such micellar systems are considered. The key research problems of micellar enzymology are formulated and its relation to enzyme membranology is discussed. Finally, the new potentialities are noted of applied enzymology (biotechnology) offered by application of a colloidal solution of water in organic solvents as a microheterogeneous medium for enzymatic reactions.Until now the development of molecular enzymology has been mainly directed to studying free enzymes [l -41. In other words, the most valuable experiments aimed at elucidating the structure of catalytic centers and the physico-chemical mechanisms of biocatalysis were successful only with the enzymes isolated from the living cells in quite a pure form. However, such 'pure' experiments, as was noted time and again [5], naturally raise the question as to whether the enzyme properties observed in vitro can be correlated adequately with the conditions of its functioning in vivo. Such a doubt is quite equitable since it became clear [6 -91 that the subcellular structure and the compartmentalization of enzymes play the most important role in metabolism regulation.Thus, the essence of the contradiction is that in vitro studies of enzymes are usually conducted in water (buffer). However, in the living cell, enzymes mostly act on or near the 'water/ organic medium' interface. For instance, many enzymes, if not the majority, are located on the surface of biological membranes or inside them [lo-161. Other enzymes function in mobile complexes with macromolecular components of the cell, e.g. with proteins or polysaccharides [14 -161. Generally speaking, the boundary between 'bound' and 'diffusion-free' enzymes is rather conventional, and such a classification is more methodical (depending on the ease of the enzyme isolation) than functional (the enzyme localization in the cell) [16]. The problem is that many of the enzymes bind to the membrane surface loosely and the degree of their binding depends on the concentration of metabolites [14-191. The physiological state of the cell determines not only the adsorption of some enzymes but their possible translocation through membranes [20,21]. In the adsorbed state in vivo (on the enterocyte brushborder) extracellular enzymes were found as well, such as proteases of the digestive tract, namely trypsin and a-chymotrypsin [22, 231, which up to now have remained model subjects of the classical 'in-water' enzymology.Finally, a few words about the medium in which diffusionfree enzymes function in the cell (for a review see [24]). It is not very clear why macromolecules (immunoglobulins and albumin) injected into the living cell diffuse so slowly (as in a 60% sucrose solution) [25]. The comparison of the diffusion rat...

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“…Up to now, more than 30 enzymes have been studied in reverse micelles. Most of them are hydrolases [a-chymotrypsin (Likhtenshtein et al, 1983), trypsin (Walde et al, 1988), lysozyme (Steinmann et al, 1986), lipase (Han & Rhee, 1986)], dehydrogenases [alcohol dehydrogenase (Malakhova et al, 1983;Samama et al, 1987), 20,-hydroxysteroid dehydrogenase (Hilhorst et al, 1984)] or oxidases [peroxidase (Martinek et al, 1981), lipoxygenase (Kurganov et al, 1985), polyphenol oxidase (Sanchez-Ferrer et al, 1988)].…”

Section: Introductionmentioning

confidence: 99%

A theoretical study on the expression of enzymic activity in reverse micelles

Bru

Sánchez‐Ferrer

García‐Carmona

1989

Biochemical Journal

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The present work deals with a theoretical model of catalysis by enzymes entrapped in reverse micelles. Three aspects of the enzyme-reverse-micelle system have been considered: structure, dynamics and enzyme distribution and catalysis in reverse micelles. A proposed structural model of reverse micelles [El Seoud (1984) in Reverse Micelles (Luisi, P. L. & Straub, B. E., eds.), p. 81, Plenum Press, New York] consists of three domains: surfactant apolar tails, bound water and free water. Dynamics are based on a dynamic equilibrium of association-dissociation that lead one to consider the dispersed polar phase as a pseudo-continuous phase [Luisi, Giomini, Pileni & Robinson (1988) Biochim. Biophys. Acta 947, 207-246]. Enzyme is distributed among the reverse-micelle domains and it expresses a catalytic constant for each one of them. The overall activity is calculated taking into account the volume in which enzyme is solubilized, and expressed as a function of the whole volume (V). The characteristic parameters of reverse micelles, omega 0 (= [H2O]/[surfactant]) and theta (= % water, v/v), were investigated as modulators of enzymic activity. Three basic patterns of modulation by omega 0 were found depending on which domain the enzyme expressed the highest catalytic constant. Combinations of those basic patterns lead to other modulation types that can be found experimentally, such as superactivation. Other combinations predict behaviour patterns not described to date, such as superinhibition. Dependence of catalytic activity on theta was only stated at omega 0 values around a critical value, which coincides with the appearance of free water.

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A novel approach to study of action of water-insoluble inhibitors of enzymic reactions

Cited by 32 publications

References 5 publications

Kinetic models in reverse micelles

Kinetic models in reverse micelles

Micellar enzymology

A theoretical study on the expression of enzymic activity in reverse micelles

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