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Activity |
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| The effectiveness of Natto Extract products is
often difficult to compare because there is no standard test
for products that
help to optimize blood viscosity. Many companies marketing nattokinase
compounds measure the enzymatic activity of their product in
Fibrinolytic Units (FU), making the assumption that the effectiveness
of these enzyme supplements lies solely in the degree with which
they can break up fibrin. This is misleading, however, because: |
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| 1. |
Fibrinolysis is just one of the in vitro activities
of nattokinase. In vivo, it can have differing activities
and functions. |
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| 2. |
Fibrin is an insoluble protein and does not allow formation
of uniform suspensions or plates. This makes it unsuitable
for a substrate for quantifying enzymatic activity. It should
therefore only be used as a substrate for qualitative analysis. |
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| 3. |
Fibrin suspensions or plates have a network structure,
and so it is unclear whether the enzymatic activity is associated
with the degradation of the network structure or that of
fibrin monomers. |
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| 4. |
When fibrin is used as the substrate, the reaction proceeds
in a logarithmic manner against the enzyme concentration.
Thus, a linear standard curve is not obtained, resulting
in an accuracy problem. |
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| 5. |
When fibrin is used as the substrate, reactivity is likely
to vary according to the enzymes used. Because there are
multiple types of nattokinase, standards for all of these
types is necessary. (Current analysis is based on a certain
standard product of unknown origin.) |
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| For these reasons, instead of giving the activity of NKCP NattoTabs
in FU, Daiwa uses two other methods to determine activity, which
results in a much more accurate assessment of their product: |
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| 1. |
Method for determining peptidase activity |
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The sample is incubated at 37°C for
5 minutes with the synthetic chromogenic substrate S-2251
(H-D-valyl-L-leucyl-L-lysine-p-nitroanilide
dihydrochloride) as substrate and the PNA, which is freed
by hydrolysis, is determined by measuring the absorbance
at 405 mm.
Peptidase activity (unit/gm) is defined 1 unit when 1nmol
of pNA per minute is freed from the substrate of 2mM S-2251
at 37°C by 1gm NKCP NattoTabs.
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| 2. |
Method for determining functional ingredients (antigen
measurement method) |
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The natto bacillus-produced protein responsible for NKCP NattoTabs'
peptidase activity is purified to prepare antibodies specific
for rabbits and mice. The amount of antigen reacting with
the specific NKCP NattoTabs antibodies is determined using
the sandwich ELISA method. The functional ingredients are
represented as μg/g or mg/kg. |
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