Toggle Main Menu Toggle Search

ePrints

Reactivity of the Cu-II and tyrosyl free-radical active site of the enzyme macromolecule galactose oxidase (GOase)

Lookup NU author(s): Craig Wright, Emeritus Prof Alfred Sykes

Downloads

Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


Abstract

Studies on the single Cu enzyme galactose oxidase (68kDa; 639 amino acids) from fungal Fusarium NRRL 2903 are considered. The enzyme reacts as a 2e(-) oxidase and catalyses the oxidation of primary alcohols such as D-galactose, RCH2OH + O-2 --> RCHO + H2O2. The Cu-II, similar to 8 Angstrom from the surface, is accessed by a channel, which imposes stereospecific selectivity (e.g. no reaction is observed with L-galactose). The Cu-II is coordinated by Tyr-272, Tyr-495, His-496, His-581 and H2O (the substrate binding site) in a square pyramidal geometry. The active enzyme has a tyrosyl (Tyr) radical at 272, which together with the Cu-II gives the required two-equivalent redox activity. The active form of the enzyme, GOase(ox),, is reformed by the 2e(-) oxidation O-2 --> H2O2. Acid-base properties of the coordinated Tyr-495 and H2O, and binding of NCS-, N-3(-), CH3CO2- and H2PO4- in place of H2O are considered.


Publication metadata

Author(s): Wright C, Sykes AG

Publication type: Article

Publication status: Published

Journal: Macromolecular Symposia

Year: 2000

Volume: 156

Pages: 263-268

ISSN (print): 1022-1360

ISSN (electronic):

Publisher: Wiley - VCH Verlag GmbH & Co

URL: http://dx.doi.org/10.1002/1521-3900(200007)156:1<263::AID-MASY263>3.0.CO;2-V

DOI: 10.1002/1521-3900(200007)156:1<263::AID-MASY263>3.0.CO;2-V


Altmetrics

Altmetrics provided by Altmetric


Actions

    Link to this publication


Share