Cosolvent control of substrate inhibition in cosolvent stimulation of β-glucuronidase activity

Pesheck, Peter S.; Lovrien, Rex

doi:10.1016/0006-291x(77)90174-7

Cited by 11 publications

(4 citation statements)

References 6 publications

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“…Organic solvent-dependent enhancement of substrate specificity has been reported in other systems (Tan & Lovrien, 1972), but the mechanisms are unclear (Pesheck & Lovrien, 1977). In fact, dramatic rate enhancements with organic cosolvent systems are well-known.…”

Section: Discussionmentioning

confidence: 99%

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Effect of organic solvents on the beef heart mitochondrial adenosine triphosphatase

Schuster¹

1979

Biochemistry

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The effect of organic solvents on the beef heart mitochondrial ATP-base-catalyzed ATP and ITP hydrolysis was examined. It was observed that numerous organic solvents stimulated ATP hydrolysis while ITP hydrolysis was inhibited. Methanol at 20% (v/v) was found to stimulate ATP hydrolysis by over 300%, while at the same methanol concentration ITP hydrolysis was inhibited approximately 50%. In the presence of 20% methanol, ATP hydrolysis exhibited linear plots of 1/[ATP] vs. 1/v, while in the absence of methanol negative cooperativity was observed. These data can be interpreted to imply that the catalytic and regulatory sites of the mitochondrial ATPase are being dissociated 20% methanol. The effect of methanol on the hydrolysis of ATP and ITP was examined as a function of pH. It was found that, at high pH in totally aqueous solutions, the hydrolysis of ATP and ITP was inhibited, while the presence of 20% methanol either caused the hydrolytic rate to peak and remain constant above pH 8 (with ATP as substrate) or caused the rate of hydrolysis to continue to increase above pH 8 (when ITP was the substrate). These data are interpreted to indicate that an acidic group in the active site may be ionizing, limiting the ATPase-catalyzed hydrolytic rate, and, with 20% methanol, this ionization was inhibited.

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Section: Discussionmentioning

confidence: 99%

“…However, such explanations appear rather speculative. Recently, Pesheck & Lovrien (1977) have suggested that, at least in the case of cosolvent stimulation of /3-glucuronidase, binding properties are affected to the same extent as Fmax.…”

Section: Discussionmentioning

confidence: 99%

Effect of organic solvents on the beef heart mitochondrial adenosine triphosphatase

Schuster¹

1979

Biochemistry

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“…Previously, Pesheck, P. et al . 30 observed that t-butanol could increase the activity of β -glucuronidase by 9-fold. Although t-butanol could increase the V max of the conversion from ES to P, the activation of β -glucuronidase by t-butanol is mainly due to a decrease in the inactive form ES2, which reduces the substrate inhibition effect.…”

Section: Discussionmentioning

confidence: 98%

Identification of isoliquiritigenin as an activator that stimulates the enzymatic production of glycyrrhetinic acid monoglucuronide

Wang

Huo

et al. 2017

Sci Rep

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Glycyrrhetinic acid monoglucuronide (GAMG) is a great value-added and has considerable commercial interest due to its strong pharmacological activities and functional low-calorie sweetener. However GAMG is quite rare in natural plants, and it must be prepared from glycyrrhizin (GL) by hydrolysing one terminal glucuronic acid. β-Glucuronidase is the key enzyme in the biotransformation of GL to GAMG, but its activities need to be enhanced to facilitate the industrial large-scale production of GAMG. In this study, we identified that isoliquiritigenin (ISL), as one of chemical compositions from the total flavonoids glycyrrhiza (TFG), can significantly enhance β-glucuronidase activity in vitro. Measurements using high-performance liquid chromatography (HPLC) showed that the activity of β-glucuronidase could be increased by 2.66-fold via the addition of ISL to a β-glucuronidase solution that contained GL at a 3:10 molar ratio of ISL to GL. ISL was concluded to be an activator because ISL could reduce the Km and Ea of β-glucuronidase reacting with GL. This study sheds new light on the mechanism of β-glucuronidase and helps to make industrial production of GAMG through fermentation feasible.

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“…When a substrate is hydrophobic and thus insoluble in water, its conversion via enzymatic reaction is significantly reduced because the enzyme is typically water soluble and the substrate is present at a very low concentration in the aqueous phase. To enable catalytic conversion of such a hydrophobic substrate, a biphasic system consisting of water and organic solvent is required 5–7 . However, slow mass transfer due to the limited interfacial area between two immiscible liquid phases significantly limits efficient conversion 8–10 .…”

Section: Introductionmentioning

confidence: 99%

Bicontinuous Interfacially Jammed Emulsion Gels (bijels) as Media for Enabling Enzymatic Reactive Separation of a Highly Water Insoluble Substrate

Cha

Lim

Haase

et al. 2019

Sci Rep

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Although enzymes are efficient catalysts capable of converting various substrates into desired products with high specificity under mild conditions, their effectiveness as catalysts is substantially reduced when substrates are poorly water-soluble. In this study, to expedite the enzymatic conversion of a hydrophobic substrate, we use a bicontinuous interfacially jammed emulsion gel (bijel) which provides large interfacial area between two immiscible liquids: oil and water. Using lipase-catalyzed hydrolysis of tributyrin as a model reaction in a batch mode, we show that bijels can be used as media to enable enzymatic reaction. The bijel system gives a four-fold increase in the initial reaction rate in comparison to a stirred biphasic medium. Our results demonstrate that bijels are powerful biphasic reaction media to accelerate enzymatic reactions with various hydrophobic reagents. This work also demonstrates that bijels can potentially be used as reaction media to enable continuous reactive separations.

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Cosolvent control of substrate inhibition in cosolvent stimulation of β-glucuronidase activity

Cited by 11 publications

References 6 publications

Effect of organic solvents on the beef heart mitochondrial adenosine triphosphatase

Effect of organic solvents on the beef heart mitochondrial adenosine triphosphatase

Identification of isoliquiritigenin as an activator that stimulates the enzymatic production of glycyrrhetinic acid monoglucuronide

Bicontinuous Interfacially Jammed Emulsion Gels (bijels) as Media for Enabling Enzymatic Reactive Separation of a Highly Water Insoluble Substrate

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