Polymer Effects under Pressure. 2. Enzymelike Catalysis in the Hydrolysis of Phenyl Ester by Copolymer Containing Imidazole

Taniguchi, Yoshihiro; Shimokawa, Kiyokazu; Hisatome, Hideo; Tanamachi, Shyoichi; Suzuki, K.

doi:10.1021/ma60064a039

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…Taniguchi et al reported that the AV* values for the polymer-catalyzed ester hydrolysis were smaller than that of the imidazole-catalyzed one and attributed this to rupture of the hydrophobic interaction. 22 The polymer catalyst they used was a copolymer of l-vinyl-2-methylimidazole and 1-vinylpyrrolidone (MI-VP). The polymer catalysts we examined here have both imidazole and carboxyl groups and resemble enzymes that have esterase actvities greater than that of the catalyst of Taniguchi et al AV* of PNPA hydrolysis catalyzed by a-chymotrypsin was reported to be -6 mL-mol™123 and was quite a bit less negative than that by imidazole (-16 mL-mol™1,22 -21 mL-mol™1 (this work)).…”

Section: Resultsmentioning

confidence: 99%

Desolvation effects in the esterolysis catalyzed by imidazole-containing polymers

Kitano¹,

Sun²,

Ise³

1983

Macromolecules

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Catalytic effects of poly(acrylic acid-co-N-acryloylhistamine) (His-AA) or a terpolymer of acrylic acid, N-acryloylhistamine, and (V-acryloyl-n-hexylamine (Ce-His-AA) on the hydrolyses of p-nitrophenyl acetate (PNPA) or Ñ-carbobenzoxy-L-phenylalanine p-nitrophenyl ester (Z-Phe-ONP) are examined at various temperatures and pressures. In the hydrolysis of PNPA, all catalysts accelerate the reaction linearly with their concentration, whereas in the hydrolysis of Z-Phe-ONP catalyzed by C6-His-AA, a saturation phenomenon is observed because of a complexation process like enzyme catalysis due to the hydrophobic interaction between the substrate and the catalyst. By double-reciprocal plots, both the reaction rate and dissociation constant of the substrate-catalyst complex are determined. Comparison of thermodynamic parameters such as AH*, AS*, AV*, AH, AS, and AV of these polymeric reaction systems with those of imidazole-catalyzed ones shows an increase in AV* and a decrease in AS*, which suggest the important role of the desolvation effect and the restricted conformation effect of the ionic polymer catalyst, respectively.

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Section: Resultsmentioning

confidence: 99%

Desolvation effects in the esterolysis catalyzed by imidazole-containing polymers

Kitano¹,

Sun²,

Ise³

1983

Macromolecules

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Catalytic effects of cationic polymeric liposomes on the alkaline hydrolysis of aniomic phenyl esters

et al. 1984

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Alkaline hydrolyses of anionic phenyl esters such as 4-acetoxy-3-nitrobenoic acid and 4-butyryloxy-3-nitrobenzoic acid were examined in the presence of cationic and polymeric liposomes, liposomes of low molecular weight compounds, and micelles. All the additives accelerate the reaction due to the hydrophobic interaction between substrates and additives and the electrostatic interaction both between substrates and additives and between OHand additives. In the Arrhenius plots of the reactions catalyzed by the liposomes, discontinuous regions were observed due to the phase transition of liposomes from the gel state to the liquid crystal state. Activation parameters A H * , AS *, and A V* for these reaction systems were evaluated. Both A S * and A V * values increase upon the addition of cationic liposomes and micelles. These results were attributed to the desolvation of the activated complex by the strong electrostatic affinity to the cationic colloidal additives.

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Polymer Effects under Pressure. IV. The Hydrolysis of Phenyl Esters Catalyzed by α-Chymotrypsin up to 2000 bar

Taniguchi¹,

Suzuki²

1980

Bulletin of the Chemical Society of Japan

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The rates of the hydrolysis of 2-valeryloxy(C5)- and 2-heptanoyloxy(C7)-benzoic acids catalyzed by α-chymotrypsin (α-CHT) were measured at pressures up to 2000 bar at 30 °C and pH 7.8 in a 0.05 M Tris buffer solution. The apparent Michaelis constant, Kmapp, was estimated to vary from 5.9 to 9.9 mM, and kcat from 11×10−3 to 52×10−3 s−1, for the C5 ester, and Kmapp, from 4.7 to 10 mM, and kcat from 37×10−3 to 200×10−3 s−1, for the C7 ester, between 1 and 2000 bar. From the pressure dependences of Kmapp and kcat, the volume changes accompanying the dissociation of the enzyme–substrate complex and the activation volume for the process of the product formation were calculated to be −6.3±2 and −20±2 cm3/mol for the C5 ester and −9.5±2 and −21±2 cm3/mol for the C7 ester. The effects of the pressure on the hydrolysis of p-nitrophenyl acetate (PNPA) catalyzed by α-CHT have also been measured up to 3000 bar at pH 7.8 in a 0.05 M Tris buffer solution and at 25 °C and 35 °C. The activation volumes were −3 cm3/mol at 25 °C and −4 cm3/mol at 30 °C and 25 °C. These results were discussed on the basis of the X-ray study of the enzyme-substrate complex.

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Polymer Effects under Pressure. 2. Enzymelike Catalysis in the Hydrolysis of Phenyl Ester by Copolymer Containing Imidazole

Cited by 4 publications

References 2 publications

Desolvation effects in the esterolysis catalyzed by imidazole-containing polymers

Desolvation effects in the esterolysis catalyzed by imidazole-containing polymers

Catalytic effects of cationic polymeric liposomes on the alkaline hydrolysis of aniomic phenyl esters

Polymer Effects under Pressure. IV. The Hydrolysis of Phenyl Esters Catalyzed by α-Chymotrypsin up to 2000 bar

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