title: Laccase: enzyme revisited and function redefined.
abstract: One enzyme, one physiological role, that's how most scientists have traditionally looked at it but there is a growing appreciation that some enzymes "moonlight" i.e. in addition to their "primary" catalytic function, they carry other functions as well. Moonlighting refers to a protein that has multiple functions, which are not because of gene fusion; splice variants or multiple proteolytic fragments. Until recently laccases were reported from eukaryotes, e.g. fungi, plants, insect. However there is some evidence for its existence in prokaryotes, a protein with typical features of multi-copper oxidase enzyme family. The present available knowledge of its structure provides a glimpse of its plasticity, revealing a multitude of binding sites responsible for multifunctional activity. Laccase represents an example of a 'moonlighting' protein that overcomes the one gene-one structure-one function concept to follow the changes of the organism in its physiological and pathological conditions. It is wide spread in plants, where it is involved in biosynthesis of lignin; in fungi it is involved in lignin degradation, development associated pigmentation (melanin synthesis), detoxification and pathogenesis, and in bacteria, laccases are involved in the synthesis of endospore coat protein (cot A).
authors.affiliation: Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110 021 India.
authors.forename: Krishna Kant
authors.initials: KK
authors.lastname: Sharma
authors.forename: Ramesh Chander
authors.initials: RC
authors.lastname: Kuhad
keywords: Isozyme; Laccase; Lignification; Moonlight; Oxidoreductase