SMCC结构反应解释Word文档格式.docx
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its
water-soluble
analog
are
heterobifunctional
crosslinkers
that
contain
N-hydroxysuccinimide
(NHS)
ester
maleimide
groups
allow
covalent
conjugation
of
amine-
sulfhydryl-containing
molecules.
NHS
esters
react
with
primary
amines
pH
7-9
to
form
amide
bonds,
while
maleimides
sulfhydryl
6.5-7.5
stable
thioether
bonds.
In
aqueous
solutions,
hydrolytic
degradation
a
competing
reaction
whose
rate
increases
pH.
The
group
more
than
the
NHS-ester
but
will
slowly
hydrolyze
loses
specificity
for
sulfhydryls
values
>
7.5.
For
these
reasons,
conjugations
usually
performed
7.2-7.5,
(amine-targeted)
reacted
before
or
simultaneous
(sulfhydryl-targeted)
reaction.
cyclohexane
ring
in
spacer
arm
reagents
decreases
hydrolysis
compared
similar
do
not
this
ring.1
This
feature
enables
proteins
have
been
maleimide-activated
be
lyophilized
stored
later
molecule.
Many
protein
products
produced
manner
(see
Related
Products).
often
used
prepare
antibody-enzyme
hapten-carrier
conjugates
two-step
scheme.
First,
amine-containing
several-fold
molar
excess
crosslinker,
followed
by
removal
(nonreacted)
reagent
desalting
dialysis;
finally,
molecule
added
already
attached
first
protein.
soluble
water
many
other
buffers
approximately
10
mM,
although
solubility
increasing
salt
concentration.
directly
must
dissolved
an
organic
solvent
such
as
dimethylsulfoxide
(DMSO)
dimethylformamide
(DMF);
subsequent
dilution
into
buffer
generally
possible,
most
reactants
remain
if
final
concentration
less
10%.
Important
Information
•
moisture-sensitive.
Store
vial
desiccant.
Equilibrate
room
temperature
opening
avoid
moisture
condensation
inside
container.
Dissolve
needed
amount
use
it
immediately
occurs.
Discard
any
unused
reconstituted
reagent.
Do
solution.
No-Weigh
Microtube
Handling:
Immediately
use,
puncture
microtube
foil
pipette
tip,
add
200
µ
l
mM
sodium
phosphate
(pH
7.0-7.5)
ultrapure
up
down
mix.
After
cut
from
strip
discard.
pouch
provided.
Note:
phosphate-buffered
saline
(PBS)
initial
dissolution
Sulfo-SMCC;
does
dissolve
well
exceeding
total
salts.
However,
once
dissolved,
solution
can
further
diluted
PBS
non-amine
buffers.
Avoid
containing
(e.g.,
Tris
glycine)
during
conjugation,
because
they
compete
intended
If
necessary,
dialyze
desalt
samples
appropriate
phosphate-
buffered
(PBS).
Molecules
moiety
free
(reduced)
sulfhydryls.
Reduce
peptide
disulfide
bonds
Immobilized
TCEP
Disulfide
Reducing
Gel
(Product
No.
77712).
proteins,
reduce
using
5
(1:
100
Bond-Breaker®
Solution,
77720)
30
minutes
temperature,
two
passes
through
suitable
column
Zeba™
Desalt
Spin
Columns).
Be
aware
antibodies)
may
inactivated
complete
reduction
their
Selective
hinge-region
IgG
accomplished
2-Mercaptoethylamine•HCl
(2-MEA,
20408).
Sulfhydryls
molecules
N-succinimidyl
S-acetylthioacetate
(SATA,
26102)
2-iminothiolane•HCl
(Traut’s
Reagent,
26101),
which
modify
amines.
Procedure
Two-step
Protein
Crosslinking
Generally,
10-
50-fold
crosslinker
over
results
sufficient
activation
enable
several
conjugated
each
More
dilute
solutions
require
greater
fold
achieve
same
level.
Empirical
testing
necessary
determine
optimal
levels
ratios
application.
A.
Material
Preparation
Conjugation
Buffer:
(PBS
=
phosphate,
150
chloride,
7.2;
e.g.,
28372)
sulfhydryl-free
Information)
–
adding
EDTA
1-5
helps
chelate
divalent
metals,
thereby
reducing
formation
Desalting
separate
modified
byproducts
Zeba
Columns)
Amine-containing
(Protein-NH2)
(Protein-SH)
B.
Protocol
best
results,
ensure
Protein-SH
prepared
ready
combine
Protein-NH2
step
5.
1.
Prepare
Buffer.
2.
Add
determines
use.
Suggested
excesses
follows
(also
see
Table
1):
<
mg/ml
40-80-fold
excess.
1-4
20-fold
excess.
5-10
5-
10-fold
Crosslinker
preparation
ml
sample.
denoted
parentheses;
then
listed
volume
example,
contents
prescribed
per
products,
dry
weighed
on
balance
2.4
500
buffer).
Concentration
(based
kDa
protein)
0.5
Molar
Excess
5X
20X
50X
(in
water)
(4.8
mg/ml*)
40
(10
20
25
DMSO
DMF)
(3.7
(1.5
(1.8
*Concentration
completely
dissolve,
place
tube
under
hot
running
incubate
50°
C
bath.
3.
Incubate
mixture
hours
4.
Remove
equilibrated
Combine
mix
desalted
ratio
corresponding
desired
conjugate
consistent
relative
number
activated
exist
proteins.
6.
there
no
harm
allowing
proceed
overnight,
specified
time.
To
stop
completion,
reduced
cysteine
times
Protein-SH.
efficiency
estimated
electrophoresis
separation
staining.
Additional
Please
visit
Pierce
website
additional
information
including
following
item:
Tech
Tip:
Attach
antibody
onto
glass,
silica
quartz
surface
scheme
Maleimide-activated
Antibody
Antibody-enzyme
Conjugate
Sulfo-SMCCAntibodyAntibody
AntibodyEnzyme
Enzyme
Figure
conjugating
enzyme
Sulfo-SMCC.
produce
mal