Vol. 82, No. 3, 1978
BIOCHEMICAL
AND BIOPHYSICAL
RESEARCH COMMUNICATIONS
June 14,1978
Pages
ESSENTIAL
ARGINY
IN
C. L.
Borders,
Department Received Yeast
2
Jr.
YEAST
, Mary
of
Chemistry,
April
7,
1978
enolase
is
rapidly
L
901-906
RESIDUES
ENOLASE’
L.
Woodal13,
College
inactivated
and
of
Wooster,
by
butanedione
Alfred
L.
George,
Wooster,
in
Ohio
borate
3
Jr.
44691
buffer,
com-
plete inactivation correlating with the modification of 1.8 arginyl residues per subunit. Protection against inactivation is provided by either an equilibrium mixture of substrates or inorganic phosphate, a competitive inhibitor of the enzyme. Complete protection by substrates correlates with the shielding of 1. 3 arginyl residues per subunit, while phosphate protects 1. 0 arginyl residue per subunit from modification.
Arginyl
residues
cofactors
and
by
a recent
with
the
of arginyl
play
substrates
report glycolytic residues
has
nary
data
further
5),
been
all
(6),
characterization
on of the
functional
(l-3).
This
one
binding fact
of fourteen
is
(3). in
of
associated
To
date
hexokinase
(4),
glyceraldehyde-3-phosphate
phosphoglycerate
enolase
role
of the
obtained
from
However, The
(3).
(lo), till
work
essential
the
role
fructose-
dehydrogenase
mutase
(11).
anionic
emphasized
enzymes
residues
characterized
dehydrogenase
available
but
the
arginyl
thoroughly
(8,9),
in
sites
essential
aldolase
lactate
role
active that
have
kinase and
have
enzyme
been
(3,
(l),
general
suggests
pathway
phosphoglycerate
drogenase
to
which
1, 6-bisphosphatase (7),
a very
now
reported
arginyl
alcohol only
prelimi-
herein
residues
dehy-
is in
a
yeast
enolase. MATERIALS
AND
METHODS
2-Phosphoglycerate 1 Acknowledgement administered by 2 To whom inquiries
was
is made to the American should
3Taken in part from the and A. L. George (1978),
be senior The
the Donors Chemical
Sigma
of the Society,
and
phosphoenolpyruvate
was
Petroleum Research for support of this
Fund, research.
addressed. Independent College of
Study Wooster
theses
of
M.
L.
Woodall
(1977)
0006-291X/78/0823-0901$01.00/0 901
Copyright All rights
0 1978 by Academic Press, Inc. of reproduction in any form reserved.
Vol. 82, No. 3, 1978
BIOCHEMICAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
2, 3-Butanedione was purchased from Aldrich. All other from Calbiochem. chemicals were reagent grade. Yeast enolase, from Sigma, was determined to It gave an amino acid analysis be >95% pure by gel electrophoresis (12). consistent with publis-:ed v,ties (13,14) and exhibited a specific activity of 70140 pmole PEP4* min erng under the conditions of assay. The samples used for amino acid analysis had an activity of 125. Enolase concentration was determined from absorbance at 280 nm, using A(O.l%) = 0.89 (15) and a molecular weight of 88, 000 for the dimeric enzyme (16). Enzymatic activity was determined at 25O by a slight modification of published procedures (17). A standard assay mixture (1.0 ml) contained the following: 50 mM Tris chloride, pH 7.8, 2.0 mM 2-PGA, 1 mM MgC12, 0.01 mM EDTA. Assays were initiated by the addition of enolase (ca. 0.5 pg) and activity determined from the increase in absorbance at 240 nm as a function of time, using a molar absorption coefficient of 1,400 for
PEP
in
1 mM
Mg”,
pH
7.8
(18).
Modification with butanedione was given in the figure and table legends. by analysis on a Beckman 120C amino published procedures (2).
carried Modification acid
out
at
25’ under of arginine
analyzer
after
the was
workup
conditions determined analogous
to
RESULTS The in
50
time
mM
course
borate,
Activity
is
after
mixture,
the
rate
ditions
of
to
two
is
the
activity if
the
column
activity
infra) ence 4
in
suggests
identical
to
that
replaced
in by
with
50 mM
4 hr
and
90
in Figure
is
gel
is no
is
due
modification 1.
However, Under
mM
modified
con-
borate,
8.3,
reactivation
is
8%
of the
a Sephadex
62% after
of the
native
15 hr.
If gel
observed.
modification
80% by
to
through
observed
to the
50
1.
Inactivation
filtered pH
the
of
Figure
11% activity
omitted.
buffer.
chloride,
however,
inactivation
shown
presence
in
only
from
enzyme
% activity
and
is
butanedione
shown
omitted
BICINE
then
Tris
is
borate
the
If the and
borate,
if
17%
reversible.
that
is
reduced to
8.3,
4 mM
of
This essential
residues. Protection
ture
after
performed
strongly
MgC12
butanedione-borate
restored is
arginyl
also
is
pH
by
17 minutes,
If
reduced
borate
equilibrated
is
filtration data
by
after
significantly
enolase
EDTA,
control
is
is
is
activity
of the
mM
modification.
inactivation
butanedione-borate
G-25
50%
of yeast
0.01
of inactivation
remains
control
inactivation
MgC12,
hours
rate
where
activity
the
1 mM
reduced
remains
the
for
of
against
substrates
or
(Figure of an
Abbreviations glycerate;
inactivation
1).
by
After
equilibrium
P.,
1
used are: inorganic
is
phosphate, 2 hr, mixture
provided
by
a competitive 75%
of the
of
substrates
902
inhibitor
control
PEP, phosphoenolpyruvate; phosphate; Tris, tris
either
activity plus
Mg 2+
an
equilibrium of
mix-
enolase
remains k enerated
(vide
in
the by
2-PGA, 2-phospho-(hydroxymethyl)aminomethane.
pres-
adding
Vol. 82, No. 3, 1978
BIOCHEMICAL
AND BIOPHYSICAL
RESEARCH COMMUNICATIONS
\ \ 07
02
1.0 L;ARG/SUWNIT
O
i 3
FIGURE 1: Yeast enolase inactivation by butanedione. The enzyme was modified by 4 mM butanedione in 50 mM borate, 1 mM MgC12, 0. 01 mM EDTA, pH 8. 3, either in the absence (e) of substrates or inhibitor, or the presence of (&2-PGA, 20 mM, or (m) Pi, 100 mM. The control enzyme retains full activity over this period of time. FIGURE 2: Correlation of yeast enolase modification by butanedione. The enzyme, mM butanedione in 50 mM borate, 1 mM and aliquots were withdrawn periodically and subsequent analyses as described in modified is given per subunit of enzyme.
2-PGA,
20
mM,
compared plus
to
only
MgC12,
nificant in
by
the
in
50
(data
0.4
not
shown).
after
are in
to with
either
Table
the
I are
while
by obtained.
both
the
extent
enolase 8. 3,
is 16%
2-PGA, 70%
inhibition
or
Pi,
inactivation After
presence after
100
mM,
hr.
It is
sig-
two
against
of protection
is
by
activity
activity
of Pi,
protection
modified
2 mM,
4 mM
remains or
inacti-
increased butanedione
after
PEP,
remains
indicates
of 1. 8 arginyl
mM,
the
modification)
one
4 mM,
after
hr
55%
one
hr
if
MgC12,
substrate.
modification 20
but
of
of
significant
pH
either
complete
2-PGA,
characterized
hr,
with
remains
MgC12,
presence one
included
activity provide
EDTA,
initiation In
control PEP
the
absence.
When
mM
In the
Extrapolation
When
or
of added
0.01
remains
correlates
of the
inactivation with arginine 30 pM, was incubated with 2 MgC12, 0.01 mM EDTA, pH 8. 3, and subjected to gel filtration Table I. The number of arginines
before
their
of magnesium.
borate,
is
in
2-PGA
absence
mM
mM,
55%
either
the
1 mM,
11% activity
presence
activity
MgC12,
1 mM,
that
vation
plus
in
110 min
100
is amino
of modification
903
inactivation
residues
mM,
and
that
per
present acid
and
by subunit the
analyses, by
2 mM
butanedione (Figure
2).
modifications the
results
butanedione,
shown
Vol. 82, No. 3, 1978
TABLE
I:
BIOCHEMICAL
Correlation with
of
Loss
AND BIOPHYSICAL
Yeast
Enolase
of Arginine,
and
RESEARCH COMMUNICATIONS
Inactivation
by
Protection
by
Butanedione
Substrates
and
Inhibitora
Enzyme
Contr
vlvc
Arg per Subunit
x 100
100
01
Arg per
Modified Subunit
13.2
t Butanedione
20
11 . 4
1. 8
t Butanedione t 2-PGA
80
12.2
1. 0
t Butanedione t Pi
a
1. 2
Modification of yeast enolase, 30 +l, was carried out dione in 50 mM borate, 1 mM MgCl2, 0.01 mM EDTA, absence of substrate or inhibitor or in the presence of After 110 min aliquots were subjected or Pi, 100 mM. on a column (0.9 x 20 cm) of Sephadex G-25 equilibrated 1 mM MgC12,O. 01 mM EDTA, pH 8.3, assayed borate, activity, and then hydrolyzed with 6 N HCl for 18 hr at to amino acid analysis as described in the text.
only
20%
activity
residues
per
remains subunit
modification,
80%
Pi
during
is
are
present
when
are
neither
found
activity
to
2-PGA
be
remains
modified. and
modification
or
80%
Pi
is
When
1. 0 arginyl activity
with 2 mM butanepH 8.3, in the 2-PGA, 20 mM, to gel filtration with for llO”
present
and
2-PGA residues
remains
50 mM enzymatic and subjected
and
is
present
are 1.2
1. 8 arginyl during When
modified. arginyl
residues
modified.
DISCUSSION Despite
the
structure amino
and acid
enolase
has
the
been
residues modified
presence
of Rose
of
approximately
in
metal
of information
function,
only
residues
cysteinyl are
wealth
binding
by
a few
chemical
correlated
with denaturing
residues
thought
one
shows
histidine
reports
on various have
modification
under
Bengal
available
the
modification
that per
lie
at
the
(21).
904
roles
of individual
Inactivation
active
site.
is
suggested
in
(19)
neither
Photooxidation with
the to
be
enolase
of yeast
residues
However,
correlates which
of yeast
of methionyl (20).
inactivation subunit
the
techniques.
conditions to
defined
aspects
case in
modification involved
and
the
Vol. 82, No. 3, 1978
EIOCHEMICAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
FIGURE 3:Kineticanalysis of inhibition of yeast enolase by phosphate. Assays were carried out at 250 in 50 mM borate, 1 mM MgC12, 0.01 mM EDTA, pH 8.3, either in the absence (0) or presence (I) of 10 mM Pi. Under these conditions 2-PGA exhibits a KM of 5.5 x 10m5 M while Pi is a competitive inhibitor with KI = 3.9 mM.
The
data
presented
mechanism
of action
borate
correlates
per
subunit
(Figure is
carried
(Figure
l),
and
shielding by It ing
of
by
substrates
of 2-PGA yeast
or enolase
protection
that
single
is
involved
in
PEP
when
these
against (Table
enolase
by
Pi
analysis
carried
The
suggests
in
of the
the
inhibition
to
active
with
the data
a non-competitive of yeast
905
enolase
inhibitor by
Pi
under
in
bind-
Thus,
it
carboxylate
moiety
modification
the
of
complete arginine
of inhibition (22).
I).
the
modification
of 1.0 mode
Table
against
phosphate,
the
pro-
modified,
When
shielding on
the is
(l-11).
site.
substrates
activity
sites
or
of inorganic
available is
the
presence
correlates
it
phosphate
modi-
with
role
protected
the
when
general
active
-
residues
of
are
a very
subunit
either bound
subunit
enzyme
per
60%
the
butanedione
reduced
when
per play
to
binding
previously that
(i.e.,
residues
residue
inactivation I).
correlates
subunit
greatly
to
arginyl
inactivation
residues
are
1.8
mixture
cofactors
out
approximately
against
arginyl
by
equilibrium
arginyl
and
inactivation
of an
arginyl
the
is
subunit
kinetic
known
critical
is
per
less
are
of inactivation
presence
residues
substrates
that
of
rate
residues
Complete
protection
0.8
arginyl
modification
the
complete
1. 3 arginyl
of anionic likely
in
that
enolase.
The
out
widely
is
the
2).
substrates
is
indicate
of yeast with
fication
tected
here
per of yeast
However, conditions
of
Vol. 82, No. 3, 1978
butanedione
modification
conclusively 3),
that
quite
with
the
KI
arginyl
of
mM that
that
is
the
substrates
in
it
is
1 mM
MgC12,
a competitive
Thus,
in
is
functional
mM
Pi
to
involved
EDTA,
under
interpretation
binding
arginine
0.01
inhibitor
a likely
involved
same
the
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
borate,
= 3. 9 mM. residue
conceivable
moiety
(50
demonstrates
(Figure is
BIOCHEMICAL
pH
these
conditions
of protection the
in
active
binding
enzyme-substrate
by
site, the
complex
8. 3)
and
it
P. is
phosphate of yeast
enolase.
ACKNOWLEDGEMENT This the
work
purchase
was
greatly
of the
aided
Beckman
by
120C
a grant amino
from acid
the
Research
Corporation
for
L. (1974),
Biochemistry
analyzer.
REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.
Lange, L. G., III, Riordan, J. F. 13, 4361-4370. Borders, C. L., Jr., and Riordan, Riordan, J. F., McElvany, K. D. 884-886. -195, Borders, C. L., Jr., Cipollo, K. Biochemistry 17, in press. Marcus, F. (19x), Biochemistry Stokes, A.M., Hill,%. Lobb, R. R., Eur. J. Biochem. 70, 517-522. Nagradova, 365 -368. Hjelmgren, 140. Rogers, Borders,
N. K. T., K.
and C. L.,
az
Asryants,
Strid,
L.
Weber, Jr. and
and
Westhead, Wold, F. Brake, J. Oh, S. -K*, 421-429. -310, Westhead, Wold, F.
L.,
B.
Biochemistry C. L., Jr.
Jorkasky,
15,
(1975),
W. (1972), Y. Acad. Travis,
4699-4704. Science
Neet,
K.
E. (1978),
J. F. (1976),
Biochim.
Biophys. F.E.
Biochem.
(1976),
14, (19775;
and
Riordan,
L. (1976), Arch.
B.A.
J. F.
3505-3509. A. 0. and
Arvidsson,
B. S. Biophys.
Biochem.
Biophys.
Acta Lett.
4, J.%iol.
906
-68,137-
-180, 19-25. Res.
310, (l%O),
384-421. Biochemistry
(1964), J. Biol. Chem. 239, 2464-2468. J. Biol. Chem. 227, 3x312. Biochemistry 1, 386-391. J.M. (1973): Biochim. Biophys.
Biochemistry C.E. (1957),
386 -’
Biochemistry 11, 2218-2224. Sci. 121, 404-427. J. and Lovins, R. E. (1970),
3rd Ed., 5, 499-538. W. (1941), Biochem. Z. J. and Hargrave, P. A.
E. W. and McLain, G. and Ballou, C.E. (1957), M. and Wold, F. (1962), Travis, J. and Brewer, E. W. (1965), and Ballou,
Vallee,
J. F. (1975), and Borders,
R.A.
B.H.(1977), Wilson,
Comm. 73, 978-984. Yang, P.3. and Schwert, G. Davis , B. J. (1964), Ann. N. Brewer, J. M., Fairwell, T., Biochemistry 9, 1011-1016. Wold, F. (1971): The Enzymes, Warburg, 0. and Christian, Mann, K. G., Castellino, F. 9, 4002-4007.
and
2139-2144. Chem.
227,
313-328.
Acta
1
BIOCHEMICAL
AND BIOPHYSICAL
RESEARCH COMMUNICATIONS
June 14,1978
Pages
ESSENTIAL
ARGINY
IN
C. L.
Borders,
Department Received Yeast
2
Jr.
YEAST
, Mary
of
Chemistry,
April
7,
1978
enolase
is
rapidly
L
901-906
RESIDUES
ENOLASE’
L.
Woodal13,
College
inactivated
and
of
Wooster,
by
butanedione
Alfred
L.
George,
Wooster,
in
Ohio
borate
3
Jr.
44691
buffer,
com-
plete inactivation correlating with the modification of 1.8 arginyl residues per subunit. Protection against inactivation is provided by either an equilibrium mixture of substrates or inorganic phosphate, a competitive inhibitor of the enzyme. Complete protection by substrates correlates with the shielding of 1. 3 arginyl residues per subunit, while phosphate protects 1. 0 arginyl residue per subunit from modification.
Arginyl
residues
cofactors
and
by
a recent
with
the
of arginyl
play
substrates
report glycolytic residues
has
nary
data
further
5),
been
all
(6),
characterization
on of the
functional
(l-3).
This
one
binding fact
of fourteen
is
(3). in
of
associated
To
date
hexokinase
(4),
glyceraldehyde-3-phosphate
phosphoglycerate
enolase
role
of the
obtained
from
However, The
(3).
(lo), till
work
essential
the
role
fructose-
dehydrogenase
mutase
(11).
anionic
emphasized
enzymes
residues
characterized
dehydrogenase
available
but
the
arginyl
thoroughly
(8,9),
in
sites
essential
aldolase
lactate
role
active that
have
kinase and
have
enzyme
been
(3,
(l),
general
suggests
pathway
phosphoglycerate
drogenase
to
which
1, 6-bisphosphatase (7),
a very
now
reported
arginyl
alcohol only
prelimi-
herein
residues
dehy-
is in
a
yeast
enolase. MATERIALS
AND
METHODS
2-Phosphoglycerate 1 Acknowledgement administered by 2 To whom inquiries
was
is made to the American should
3Taken in part from the and A. L. George (1978),
be senior The
the Donors Chemical
Sigma
of the Society,
and
phosphoenolpyruvate
was
Petroleum Research for support of this
Fund, research.
addressed. Independent College of
Study Wooster
theses
of
M.
L.
Woodall
(1977)
0006-291X/78/0823-0901$01.00/0 901
Copyright All rights
0 1978 by Academic Press, Inc. of reproduction in any form reserved.
Vol. 82, No. 3, 1978
BIOCHEMICAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
2, 3-Butanedione was purchased from Aldrich. All other from Calbiochem. chemicals were reagent grade. Yeast enolase, from Sigma, was determined to It gave an amino acid analysis be >95% pure by gel electrophoresis (12). consistent with publis-:ed v,ties (13,14) and exhibited a specific activity of 70140 pmole PEP4* min erng under the conditions of assay. The samples used for amino acid analysis had an activity of 125. Enolase concentration was determined from absorbance at 280 nm, using A(O.l%) = 0.89 (15) and a molecular weight of 88, 000 for the dimeric enzyme (16). Enzymatic activity was determined at 25O by a slight modification of published procedures (17). A standard assay mixture (1.0 ml) contained the following: 50 mM Tris chloride, pH 7.8, 2.0 mM 2-PGA, 1 mM MgC12, 0.01 mM EDTA. Assays were initiated by the addition of enolase (ca. 0.5 pg) and activity determined from the increase in absorbance at 240 nm as a function of time, using a molar absorption coefficient of 1,400 for
PEP
in
1 mM
Mg”,
pH
7.8
(18).
Modification with butanedione was given in the figure and table legends. by analysis on a Beckman 120C amino published procedures (2).
carried Modification acid
out
at
25’ under of arginine
analyzer
after
the was
workup
conditions determined analogous
to
RESULTS The in
50
time
mM
course
borate,
Activity
is
after
mixture,
the
rate
ditions
of
to
two
is
the
activity if
the
column
activity
infra) ence 4
in
suggests
identical
to
that
replaced
in by
with
50 mM
4 hr
and
90
in Figure
is
gel
is no
is
due
modification 1.
However, Under
mM
modified
con-
borate,
8.3,
reactivation
is
8%
of the
a Sephadex
62% after
of the
native
15 hr.
If gel
observed.
modification
80% by
to
through
observed
to the
50
1.
Inactivation
filtered pH
the
of
Figure
11% activity
omitted.
buffer.
chloride,
however,
inactivation
shown
presence
in
only
from
enzyme
% activity
and
is
butanedione
shown
omitted
BICINE
then
Tris
is
borate
the
If the and
borate,
if
17%
reversible.
that
is
reduced to
8.3,
4 mM
of
This essential
residues. Protection
ture
after
performed
strongly
MgC12
butanedione-borate
restored is
arginyl
also
is
pH
by
17 minutes,
If
reduced
borate
equilibrated
is
filtration data
by
after
significantly
enolase
EDTA,
control
is
is
is
activity
of the
mM
modification.
inactivation
butanedione-borate
G-25
50%
of yeast
0.01
of inactivation
remains
control
inactivation
MgC12,
hours
rate
where
activity
the
1 mM
reduced
remains
the
for
of
against
substrates
or
(Figure of an
Abbreviations glycerate;
inactivation
1).
by
After
equilibrium
P.,
1
used are: inorganic
is
phosphate, 2 hr, mixture
provided
by
a competitive 75%
of the
of
substrates
902
inhibitor
control
PEP, phosphoenolpyruvate; phosphate; Tris, tris
either
activity plus
Mg 2+
an
equilibrium of
mix-
enolase
remains k enerated
(vide
in
the by
2-PGA, 2-phospho-(hydroxymethyl)aminomethane.
pres-
adding
Vol. 82, No. 3, 1978
BIOCHEMICAL
AND BIOPHYSICAL
RESEARCH COMMUNICATIONS
\ \ 07
02
1.0 L;ARG/SUWNIT
O
i 3
FIGURE 1: Yeast enolase inactivation by butanedione. The enzyme was modified by 4 mM butanedione in 50 mM borate, 1 mM MgC12, 0. 01 mM EDTA, pH 8. 3, either in the absence (e) of substrates or inhibitor, or the presence of (&2-PGA, 20 mM, or (m) Pi, 100 mM. The control enzyme retains full activity over this period of time. FIGURE 2: Correlation of yeast enolase modification by butanedione. The enzyme, mM butanedione in 50 mM borate, 1 mM and aliquots were withdrawn periodically and subsequent analyses as described in modified is given per subunit of enzyme.
2-PGA,
20
mM,
compared plus
to
only
MgC12,
nificant in
by
the
in
50
(data
0.4
not
shown).
after
are in
to with
either
Table
the
I are
while
by obtained.
both
the
extent
enolase 8. 3,
is 16%
2-PGA, 70%
inhibition
or
Pi,
inactivation After
presence after
100
mM,
hr.
It is
sig-
two
against
of protection
is
by
activity
activity
of Pi,
protection
modified
2 mM,
4 mM
remains or
inacti-
increased butanedione
after
PEP,
remains
indicates
of 1. 8 arginyl
mM,
the
modification)
one
4 mM,
after
hr
55%
one
hr
if
MgC12,
substrate.
modification 20
but
of
of
significant
pH
either
complete
2-PGA,
characterized
hr,
with
remains
MgC12,
presence one
included
activity provide
EDTA,
initiation In
control PEP
the
absence.
When
mM
In the
Extrapolation
When
or
of added
0.01
remains
correlates
of the
inactivation with arginine 30 pM, was incubated with 2 MgC12, 0.01 mM EDTA, pH 8. 3, and subjected to gel filtration Table I. The number of arginines
before
their
of magnesium.
borate,
is
in
2-PGA
absence
mM
mM,
55%
either
the
1 mM,
11% activity
presence
activity
MgC12,
1 mM,
that
vation
plus
in
110 min
100
is amino
of modification
903
inactivation
residues
mM,
and
that
per
present acid
and
by subunit the
analyses, by
2 mM
butanedione (Figure
2).
modifications the
results
butanedione,
shown
Vol. 82, No. 3, 1978
TABLE
I:
BIOCHEMICAL
Correlation with
of
Loss
AND BIOPHYSICAL
Yeast
Enolase
of Arginine,
and
RESEARCH COMMUNICATIONS
Inactivation
by
Protection
by
Butanedione
Substrates
and
Inhibitora
Enzyme
Contr
vlvc
Arg per Subunit
x 100
100
01
Arg per
Modified Subunit
13.2
t Butanedione
20
11 . 4
1. 8
t Butanedione t 2-PGA
80
12.2
1. 0
t Butanedione t Pi
a
1. 2
Modification of yeast enolase, 30 +l, was carried out dione in 50 mM borate, 1 mM MgCl2, 0.01 mM EDTA, absence of substrate or inhibitor or in the presence of After 110 min aliquots were subjected or Pi, 100 mM. on a column (0.9 x 20 cm) of Sephadex G-25 equilibrated 1 mM MgC12,O. 01 mM EDTA, pH 8.3, assayed borate, activity, and then hydrolyzed with 6 N HCl for 18 hr at to amino acid analysis as described in the text.
only
20%
activity
residues
per
remains subunit
modification,
80%
Pi
during
is
are
present
when
are
neither
found
activity
to
2-PGA
be
remains
modified. and
modification
or
80%
Pi
is
When
1. 0 arginyl activity
with 2 mM butanepH 8.3, in the 2-PGA, 20 mM, to gel filtration with for llO”
present
and
2-PGA residues
remains
50 mM enzymatic and subjected
and
is
present
are 1.2
1. 8 arginyl during When
modified. arginyl
residues
modified.
DISCUSSION Despite
the
structure amino
and acid
enolase
has
the
been
residues modified
presence
of Rose
of
approximately
in
metal
of information
function,
only
residues
cysteinyl are
wealth
binding
by
a few
chemical
correlated
with denaturing
residues
thought
one
shows
histidine
reports
on various have
modification
under
Bengal
available
the
modification
that per
lie
at
the
(21).
904
roles
of individual
Inactivation
active
site.
is
suggested
in
(19)
neither
Photooxidation with
the to
be
enolase
of yeast
residues
However,
correlates which
of yeast
of methionyl (20).
inactivation subunit
the
techniques.
conditions to
defined
aspects
case in
modification involved
and
the
Vol. 82, No. 3, 1978
EIOCHEMICAL
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
FIGURE 3:Kineticanalysis of inhibition of yeast enolase by phosphate. Assays were carried out at 250 in 50 mM borate, 1 mM MgC12, 0.01 mM EDTA, pH 8.3, either in the absence (0) or presence (I) of 10 mM Pi. Under these conditions 2-PGA exhibits a KM of 5.5 x 10m5 M while Pi is a competitive inhibitor with KI = 3.9 mM.
The
data
presented
mechanism
of action
borate
correlates
per
subunit
(Figure is
carried
(Figure
l),
and
shielding by It ing
of
by
substrates
of 2-PGA yeast
or enolase
protection
that
single
is
involved
in
PEP
when
these
against (Table
enolase
by
Pi
analysis
carried
The
suggests
in
of the
the
inhibition
to
active
with
the data
a non-competitive of yeast
905
enolase
inhibitor by
Pi
under
in
bind-
Thus,
it
carboxylate
moiety
modification
the
of
complete arginine
of inhibition (22).
I).
the
modification
of 1.0 mode
Table
against
phosphate,
the
pro-
modified,
When
shielding on
the is
(l-11).
site.
substrates
activity
sites
or
of inorganic
available is
the
presence
correlates
it
phosphate
modi-
with
role
protected
the
when
general
active
-
residues
of
are
a very
subunit
either bound
subunit
enzyme
per
60%
the
butanedione
reduced
when
per play
to
binding
previously that
(i.e.,
residues
residue
inactivation I).
correlates
subunit
greatly
to
arginyl
inactivation
residues
are
1.8
mixture
cofactors
out
approximately
against
arginyl
by
equilibrium
arginyl
and
inactivation
of an
arginyl
the
is
subunit
kinetic
known
critical
is
per
less
are
of inactivation
presence
residues
substrates
that
of
rate
residues
Complete
protection
0.8
arginyl
modification
the
complete
1. 3 arginyl
of anionic likely
in
that
enolase.
The
out
widely
is
the
2).
substrates
is
indicate
of yeast with
fication
tected
here
per of yeast
However, conditions
of
Vol. 82, No. 3, 1978
butanedione
modification
conclusively 3),
that
quite
with
the
KI
arginyl
of
mM that
that
is
the
substrates
in
it
is
1 mM
MgC12,
a competitive
Thus,
in
is
functional
mM
Pi
to
involved
EDTA,
under
interpretation
binding
arginine
0.01
inhibitor
a likely
involved
same
the
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
borate,
= 3. 9 mM. residue
conceivable
moiety
(50
demonstrates
(Figure is
BIOCHEMICAL
pH
these
conditions
of protection the
in
active
binding
enzyme-substrate
by
site, the
complex
8. 3)
and
it
P. is
phosphate of yeast
enolase.
ACKNOWLEDGEMENT This the
work
purchase
was
greatly
of the
aided
Beckman
by
120C
a grant amino
from acid
the
Research
Corporation
for
L. (1974),
Biochemistry
analyzer.
REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.
Lange, L. G., III, Riordan, J. F. 13, 4361-4370. Borders, C. L., Jr., and Riordan, Riordan, J. F., McElvany, K. D. 884-886. -195, Borders, C. L., Jr., Cipollo, K. Biochemistry 17, in press. Marcus, F. (19x), Biochemistry Stokes, A.M., Hill,%. Lobb, R. R., Eur. J. Biochem. 70, 517-522. Nagradova, 365 -368. Hjelmgren, 140. Rogers, Borders,
N. K. T., K.
and C. L.,
az
Asryants,
Strid,
L.
Weber, Jr. and
and
Westhead, Wold, F. Brake, J. Oh, S. -K*, 421-429. -310, Westhead, Wold, F.
L.,
B.
Biochemistry C. L., Jr.
Jorkasky,
15,
(1975),
W. (1972), Y. Acad. Travis,
4699-4704. Science
Neet,
K.
E. (1978),
J. F. (1976),
Biochim.
Biophys. F.E.
Biochem.
(1976),
14, (19775;
and
Riordan,
L. (1976), Arch.
B.A.
J. F.
3505-3509. A. 0. and
Arvidsson,
B. S. Biophys.
Biochem.
Biophys.
Acta Lett.
4, J.%iol.
906
-68,137-
-180, 19-25. Res.
310, (l%O),
384-421. Biochemistry
(1964), J. Biol. Chem. 239, 2464-2468. J. Biol. Chem. 227, 3x312. Biochemistry 1, 386-391. J.M. (1973): Biochim. Biophys.
Biochemistry C.E. (1957),
386 -’
Biochemistry 11, 2218-2224. Sci. 121, 404-427. J. and Lovins, R. E. (1970),
3rd Ed., 5, 499-538. W. (1941), Biochem. Z. J. and Hargrave, P. A.
E. W. and McLain, G. and Ballou, C.E. (1957), M. and Wold, F. (1962), Travis, J. and Brewer, E. W. (1965), and Ballou,
Vallee,
J. F. (1975), and Borders,
R.A.
B.H.(1977), Wilson,
Comm. 73, 978-984. Yang, P.3. and Schwert, G. Davis , B. J. (1964), Ann. N. Brewer, J. M., Fairwell, T., Biochemistry 9, 1011-1016. Wold, F. (1971): The Enzymes, Warburg, 0. and Christian, Mann, K. G., Castellino, F. 9, 4002-4007.
and
2139-2144. Chem.
227,
313-328.
Acta
1
