title: Functional characterization of a yellow laccase from Leucoagaricus gongylophorus.
abstract: In this work we have identified, using mass spectrometry, two laccases produced by Leucoagaricus gongylophorus. One of them, Lac1Lg, was isolated, purified and characterized. Lac1Lg, a monomeric enzyme, was studied using ABTS and syringaldazine substrates. Lac1Lg presented kcat/Km almost threefold higher for syringaldazine than for ABTS, showing a higher catalytic efficiency of Lac1Lg for syringaldazine. The interference of several metal ions and substances in the laccase activity were evaluated. Lac1Lg did not absorb at 600 nm, which is a characteristic of so-called yellow laccases. Lac1Lg also was able to oxidize non-phenolic substrate (anthracene) in the absence of an exogenous mediator, showing that the enzyme has potential to explore in biotechnological processes. Our Lac1Lg three-dimensional molecular model, constructed using homology modeling, showed that the Lac1Lg catalytic site is very closed to blue laccases.
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP Brazil.
authors.forename: Priscila Tomie Leme
authors.initials: PT
authors.lastname: Ike
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP Brazil.
authors.forename: Ariele C
authors.initials: AC
authors.lastname: Moreira
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP Brazil.
authors.forename: Fernando G
authors.initials: FG
authors.lastname: de Almeida
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP Brazil.
authors.forename: Douglas
authors.initials: D
authors.lastname: Ferreira
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil.
authors.forename: Willian Garcia
authors.initials: WG
authors.lastname: Birolli
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil.
authors.forename: Andre Luiz Meleiro
authors.initials: AL
authors.lastname: Porto
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP Brazil.
authors.forename: Dulce Helena F
authors.initials: DH
authors.lastname: Souza
keywords: Kinetic enzyme; Leucoagaricus gongylophorus; Molecular modeling; Non-phenolic substrate; Yellow laccase