InterPro domain: IPR034285

Laccase is a blue multi-copper enzyme that catalyzes the oxidation of a variety aromatic - notably phenolic and inorganic substances coupled to the reduction of molecular oxygen to water. Laccase has been implicated in a wide spectrum of biological activities and, in particular, plays a key role in morphogenesis, development and lignin metabolism. Plants usually express multiple laccase genes, but their precise physiological/biochemical roles remain largely unclear [ 1 ]. In cotton (Gossypium spp.), laccases may be involved in fibre development [ 2 ].

Like other related multicopper oxidases (MCOs), laccase is composed of three cupredoxin domains that include one mononuclear and one trinuclear copper centre. The copper ions are bound in several sites: Type 1, Type 2, and/or Type 3. The ensemble of types 2 and 3 copper is called a trinuclear cluster. MCOs oxidize their substrate by accepting electrons at a mononuclear copper centre and transferring them to the active site trinuclear copper centre. The cupredoxin domain 2 of 3-domain MCOs has lost the ability to bind copper [ 3 , 4 ].

1. The laccase multigene family in Arabidopsis thaliana: towards addressing the mystery of their gene function(s). Planta 233, 439-70
2. Genome-wide identification of multifunctional laccase gene family in cotton (Gossypium spp.); expression and biochemical analysis during fiber development. Sci Rep 6, 34309
3. Crystal structure of the type-2 Cu depleted laccase from Coprinus cinereus at 2.2 A resolution. Nat. Struct. Biol. 5, 310-6
4. Laccases: a never-ending story. Cell. Mol. Life Sci. 67, 369-85