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BioFX
Non-Fat Dry Milk Blocks and
Diluents |
BioFX Laboratories NFDM blocks
and diluents are supplied as
concentrates.
BioFX NFDM Buffers
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Borate Buffered Saline (BBS),
working pH range of 8.0 ±
0.2
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Imidazole Buffered Saline
(IBS), working pH range of 7.0 ±
0.1
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Tris Buffered Saline (TBS),
working pH range of 7.6 ±
0.1
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Phosphate Buffered Saline
(PBS), working pH range of 7.4 ±
0.1
Notes Regarding Biological Buffers
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May specifically stimulate or
depress enzyme activity
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May interfere or react with
substrates, inhibitors or
cofactors
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Non-specifically they may
exert effects due to their ionic
strength
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Concentrations should be kept
as low as possible and maintain
pH constancy
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The medium should be adjusted
by adding appropriate inorganic
and organic ions to simulate
physiological conditions
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Borate Buffered Saline (BBS)
should not be used in the
presence of polyols, including
carbohydrates and their
derivatives with which they may chelate; BBS has a high
bacteriocidal effect; the use of
BBS in gel electrophoresis can
result in spreading of the bands
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Tris Buffered Saline (TBS),
pH 7.6, is a poor buffer below
pH 7.5 and the pH can fall more
than 1 pH unit in warming from 0°C
to 37°C;
TBS has the disadvantages of its
reactivity as a primary amine
and its appreciable solubility
in organic solvents which can
lead to an accumulation in the
biological phase of a reaction
system; to avoid complex
formation with ionic species
such as calcium and magnesium in
blood, Tris buffers are
preferable over phosphate
buffers
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Phosphate is a poor buffer
above pH 7.5; phosphate buffer
should not be used in assays
where competition for phosphate
groups, or complex formation
with a metal ion is essential
for the enzyme activation;
phosphate ions will inhibit
carboxypeptidiase, carboxylase,
urease, muscle diaminase,
formase and phosphoglucomutase
“It is impossible even to guess how
many exploratory experiments have
failed, how many reaction rates have
been depressed and how many
processes have been distorted
because of imperfections of the
buffers employed.”
Norman Good, et al.
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