Cloning and analysis of laccases from acinetobacter baumannii isolates
Ikusi/ Ireki
Data
2015-04-01Egilea
Antsotegi Uskola, Martzel
Laburpena
Laccases (benzenediol
: oxygen oxi
doreductases; EC 1.10.3.2) are
wide
spread
i
n
nature. They are usually
found in higher plants and fungi (Thurston 19
94; Mayer and
Staples 2002), but
recently some bacterial laccases have also been
found
.
The first
laccase studied was from
Rhus vernicifera
in 1883, a Japanese lacquer
tree, fr
om
which the name
laccase was derived (Yoshida
,
1883).
These enzymes
belong to the
group of
bl
ue multi
-
copper oxidases (MCOs)
.
They
usually contain
four copper atoms located in
three distinct sites.
Each site reacts
differently to light.
The Type 1 (T1) site copper atom absorbs
intensely at 600
nm
and emits
the blue
light
, the Type 2 (T2) site copper atom is
not
visible in the
absorption spectr
um and last,
the Type 3 (T3) site has two c
opper atoms and absorbs
at 330
nm
(
Santhanam
et al
.
,
2011;
Quintanar
et al
.
,
2007
)
.
The protei
n structure acts
as a complex
ligand
for the catalytic
coppers, providing them
the right structure
where changes between the reduction states are thermodynamically possible
(Dub
é
,
2008
)
.
These
enzymes
oxidize a surprisingly wide variety of organic and
inorganic
compounds like,
diphenols, polyphenols, substituted phenols, diamines and a
romatic
amines, with concomitant
reduction of molecular oxygen to water (Thurston
,
1