Research article summary (published 13 Nov 2004):

Fishing of beta-amylase with a SAM of alpha-cyclodextrin-poly- (ethylene glycol) conjugate.

Full Abstract

Alpha-cyclodextrin (alpha-CD) with an amino group was conjugated to an alpha, omega-dicarboxylated poly(ethylene glycol) (PEG). The inhibition constant (Ki) of the alpha-CD-PEG conjugate for the catalysis by beta-amylase was larger than that of alpha-CD, due to a steric obstruction of the PEG moiety to the binding of alpha-CD moiety to beta-amylase. alpha-CD-PEG was further modified with cystamine (CD-PEG-Cys) or cysteamine methyl disulfide (CD-PEG-MDS), and the disulfide-carrying alpha-CD-PEG was accumulated on a gold surface as a self-assembled monolayer (SAM). The binding of beta-amylase to the alpha-CD-PEG SAM was followed by a decrease in cathodic peak current in the voltammogram of hydroquinone as a probe using a cyclic voltammetry (CV). The beta-amylase bound to the alpha-CD-PEG SAM was desorbed by the addition of free alpha-CD, and the ratio of desorbed beta-amylase from the SAM of alpha-CD-PEG-Cys to the total amount of the enzyme bound to the SAM was 40% whereas that from the alpha-CD-PEG-MDS SAM was 83-85%. The percentage of desorption was increased to 100% by the treatment of the alpha-CD-PEG-MDS SAM-carrying electrode with 2-hydroxyethyldisulfide prior to the immersion in the enzyme solution. Adsorption and desorption processes of beta-amylase to the surface of alpha-CD-PEG-MDS SAM were clearly observed using localized surface plasmon resonance absorption spectroscopy. The binding constant of the enzyme to the surface-confined alpha-CD-PEG was much larger than that to free alpha-CD, probably due to a large local concentration of the alpha-CD moiety on the gold surface.

Author information

Author/s: Kitano, Hiromi (H); Miyamoto, Takashi (T); Kawasaki, Hideaki (H);

Affiliation: Department of Chemical and Biochemical Engineering, Toyama University, Toyama 930-8555, Japan. kitano(-atsign-)eng.toyama-u.ac.jp

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Journal of colloid and interface science (J Colloid Interface Sci), published in United States. (Language: eng)

Reference: 2004-Nov; vol 279 (issue 2) : pp 425-32

Dates: Created 2004/10/06; Completed 2005/07/25; Revised 2009/11/11;

PMID: 15464807, status: MEDLINE (last retrieved date: 11/11/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MeSH Headings (categories) shown below.

Catalysis Electrochemistry Electrodes Glass Gold - chemistry Molecular Structure

Nanostructures - chemistry Polyethylene Glycols - chemistry Surface Plasmon Resonance Surface Properties alpha-Cyclodextrins - chemistry beta-Amylase - chemistry

Note: Bold headings indicate primary MeSH headings or qualifiers.

Associated Chemicals: Polyethylene Glycols (0) ; alpha-Cyclodextrins (0) ; alpha-cyclodextrin (10016-20-3) ; Gold (7440-57-5) ; beta-Amylase (EC 3.2.1.2)

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