BIOCHEMICAL
Vol. 63, No. 4, 1975
IS HISTIDINE
Received
CARBOXYLESTERASES ?
Heymann
Biochemisches D-23
and Gerda Marcussen-Wulff
Institut
Riel,
im Fachbereich
Neue Universitat,
February
RESEARCH COMMUNICATIONS
INVOLVED IN THE CATALYTIC MECHANISM
OF UNSPECIFIC Eberhard
AND BIOPHYSICAL
Medizin,
Otto-Meyerhof-Haus
19,1975
Summary: The reaction between the liver carboxylesterases from ox and nio; and the inhibitor K-bromoacetophenone was studied J-q F‘ ? Iid analysis, A significant modification of histidine in pi"g ri#.%r esterase was not found, but there was a slight loss of some other residues. In ox liver esterase the total inhibition correlated with the loss of about 1.7 histidine residues. However, in contrast to previous results with chicken and ox esterases the specific active-site-directed inhibitor E 600 did not prevent the modification of the reactive histidine It is concluded that an earlier report on the involvement of histidine in the action of liver esterases (1) is partly incorrect or perhaps applicable only to chicken liver esterase. Willadsen
et al.
(1)
histidine
residue
in
esterases
(EC 3.1.1.1)
from of
kinetic the
behaviour esterase
of
to bear
more,
the
Abbreviation:
a histidine
results
of a single
chicken
group like
find
of the
incorporation
active
E 600 = diethyl-4-nitrophenyl
investigations
site
(1)
active are
in
between
or trypsin,
at the et al.
of this
any similarity
chymotrypsin
88?
was concluded
P4C]-bromoacetophenone,
preliminary
not
residue
This
with of the
in
and ox - liver
autoradiographic'studies
labeled
we did
of Willadsen
Copyright Q 1975 by Academic Press, Inc. AlI rights of reproduction in any form reserved.
of
qualitative
However,
and proteases
known
center
measurement
basic
modification
d-bromoacetophenone.
from
agents the
active
by
inhibitor.
alkylating
on the
of enzyme
quantitative
radioactive with
the
evidence,
hydrolysate
and from
reported
the &
which
site. in
(2)
are
Further-
disagreement
phosphate
liver
Vol.63,No.4,
with
1975
our previous
esterase
by
Since
was due to the reaction
finding
(2)
ti-bromoacetophenone
of substrate.
the
BIOCHEMICAL
it
was not
use of different
of pig
and ox liver
AND BIOPHYSICAL
that
the was not
clear
RESEARCH COMMUNICATIONS
inhibition delayed
whether
animals, esterase
of pig
this
we have with
in
the
liver presence
discrepancy re-examined o
Vol. 63, No. 4, 1975
IS HISTIDINE
Received
CARBOXYLESTERASES ?
Heymann
Biochemisches D-23
and Gerda Marcussen-Wulff
Institut
Riel,
im Fachbereich
Neue Universitat,
February
RESEARCH COMMUNICATIONS
INVOLVED IN THE CATALYTIC MECHANISM
OF UNSPECIFIC Eberhard
AND BIOPHYSICAL
Medizin,
Otto-Meyerhof-Haus
19,1975
Summary: The reaction between the liver carboxylesterases from ox and nio; and the inhibitor K-bromoacetophenone was studied J-q F‘ ? Iid analysis, A significant modification of histidine in pi"g ri#.%r esterase was not found, but there was a slight loss of some other residues. In ox liver esterase the total inhibition correlated with the loss of about 1.7 histidine residues. However, in contrast to previous results with chicken and ox esterases the specific active-site-directed inhibitor E 600 did not prevent the modification of the reactive histidine It is concluded that an earlier report on the involvement of histidine in the action of liver esterases (1) is partly incorrect or perhaps applicable only to chicken liver esterase. Willadsen
et al.
(1)
histidine
residue
in
esterases
(EC 3.1.1.1)
from of
kinetic the
behaviour esterase
of
to bear
more,
the
Abbreviation:
a histidine
results
of a single
chicken
group like
find
of the
incorporation
active
E 600 = diethyl-4-nitrophenyl
investigations
site
(1)
active are
in
between
or trypsin,
at the et al.
of this
any similarity
chymotrypsin
88?
was concluded
P4C]-bromoacetophenone,
preliminary
not
residue
This
with of the
in
and ox - liver
autoradiographic'studies
labeled
we did
of Willadsen
Copyright Q 1975 by Academic Press, Inc. AlI rights of reproduction in any form reserved.
of
qualitative
However,
and proteases
known
center
measurement
basic
modification
d-bromoacetophenone.
from
agents the
active
by
inhibitor.
alkylating
on the
of enzyme
quantitative
radioactive with
the
evidence,
hydrolysate
and from
reported
the &
which
site. in
(2)
are
Further-
disagreement
phosphate
liver
Vol.63,No.4,
with
1975
our previous
esterase
by
Since
was due to the reaction
finding
(2)
ti-bromoacetophenone
of substrate.
the
BIOCHEMICAL
it
was not
use of different
of pig
and ox liver
AND BIOPHYSICAL
that
the was not
clear
RESEARCH COMMUNICATIONS
inhibition delayed
whether
animals, esterase
of pig
this
we have with
in
the
liver presence
discrepancy re-examined o
