Multifunctional hydrolytic catalyses x. Catalytic hydrolysis of p-Nitrophenyl acetate by a polyethylenimine derivative containing hydroxamate (Zwitterionic) group

Yoshio Okahata, Toyoki Kunitake

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

A water-soluble polyethylenimine derivatives was prepared containing the zwittenionic hydroxamate group, 11 mol% dococyl side chain, and a tertiary amino group. This polymer hydrolyzes p-nitrophenyl esters very effeciently (30°C, 3 v/v% EtOHH2O), according to the Michaelis-Menten kinetics. The catalysis involves substrate binding (Km= (2-5) × 10-4M in the case of p-nitrophenyl acetate) due to hydrophobic interaction, and facile acylation and de-acylation at the hydroxamate site. The zwitterionic nature and the hydrophobic microenvironment contribute to the enchanced nucleophilicity to the hydroxamate group. It is suggested that the de-acylation process involves general-base catalysis by the tert-amino group. The overall catalytic effeciency for p-nitrophenyl acetate exceeded that of α-chymotrypsin by a factor of ca. 100 under a comparable condition. Polymers which do not contain the hydroxamate group or contain the imidazole group in its place were much less effective.

Original languageEnglish
Pages (from-to)163-175
Number of pages13
JournalJournal of Molecular Catalysis
Volume6
Issue number3
DOIs
Publication statusPublished - Sep 1979

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Acylation
Hydrolysis
Derivatives
Catalysis
Polymers
Esters
Kinetics
Substrates
Water

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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Multifunctional hydrolytic catalyses x. Catalytic hydrolysis of p-Nitrophenyl acetate by a polyethylenimine derivative containing hydroxamate (Zwitterionic) group. / Okahata, Yoshio; Kunitake, Toyoki.

In: Journal of Molecular Catalysis, Vol. 6, No. 3, 09.1979, p. 163-175.

Research output: Contribution to journalArticle

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abstract = "A water-soluble polyethylenimine derivatives was prepared containing the zwittenionic hydroxamate group, 11 mol{\%} dococyl side chain, and a tertiary amino group. This polymer hydrolyzes p-nitrophenyl esters very effeciently (30°C, 3 v/v{\%} EtOHH2O), according to the Michaelis-Menten kinetics. The catalysis involves substrate binding (Km= (2-5) × 10-4M in the case of p-nitrophenyl acetate) due to hydrophobic interaction, and facile acylation and de-acylation at the hydroxamate site. The zwitterionic nature and the hydrophobic microenvironment contribute to the enchanced nucleophilicity to the hydroxamate group. It is suggested that the de-acylation process involves general-base catalysis by the tert-amino group. The overall catalytic effeciency for p-nitrophenyl acetate exceeded that of α-chymotrypsin by a factor of ca. 100 under a comparable condition. Polymers which do not contain the hydroxamate group or contain the imidazole group in its place were much less effective.",
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N2 - A water-soluble polyethylenimine derivatives was prepared containing the zwittenionic hydroxamate group, 11 mol% dococyl side chain, and a tertiary amino group. This polymer hydrolyzes p-nitrophenyl esters very effeciently (30°C, 3 v/v% EtOHH2O), according to the Michaelis-Menten kinetics. The catalysis involves substrate binding (Km= (2-5) × 10-4M in the case of p-nitrophenyl acetate) due to hydrophobic interaction, and facile acylation and de-acylation at the hydroxamate site. The zwitterionic nature and the hydrophobic microenvironment contribute to the enchanced nucleophilicity to the hydroxamate group. It is suggested that the de-acylation process involves general-base catalysis by the tert-amino group. The overall catalytic effeciency for p-nitrophenyl acetate exceeded that of α-chymotrypsin by a factor of ca. 100 under a comparable condition. Polymers which do not contain the hydroxamate group or contain the imidazole group in its place were much less effective.

AB - A water-soluble polyethylenimine derivatives was prepared containing the zwittenionic hydroxamate group, 11 mol% dococyl side chain, and a tertiary amino group. This polymer hydrolyzes p-nitrophenyl esters very effeciently (30°C, 3 v/v% EtOHH2O), according to the Michaelis-Menten kinetics. The catalysis involves substrate binding (Km= (2-5) × 10-4M in the case of p-nitrophenyl acetate) due to hydrophobic interaction, and facile acylation and de-acylation at the hydroxamate site. The zwitterionic nature and the hydrophobic microenvironment contribute to the enchanced nucleophilicity to the hydroxamate group. It is suggested that the de-acylation process involves general-base catalysis by the tert-amino group. The overall catalytic effeciency for p-nitrophenyl acetate exceeded that of α-chymotrypsin by a factor of ca. 100 under a comparable condition. Polymers which do not contain the hydroxamate group or contain the imidazole group in its place were much less effective.

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