Biology Reference
In-Depth Information
and, by necessity, f
CaIn
þ
f
In
¼
1. Therefore,
½
CaIn
¼f
CaIn
C
T
and In
½¼f
In
C
T
¼
ð
1
f
CaIn
ÞC
T
ðA2:8Þ
The total fluorescence, F
T
, from a solution of indicator contains contributions
from both CaIn and In forms:
F
T
¼ F
CaIn
þ F
In
¼
2
:
303
Q
CaIn
e
CaIn
l
½
CaIn
I
0
þ
2
:
303
Q
In
e
In
l
½ I
0
In
¼
2
:
303
Q
CaIn
e
CaIn
lf
CaIn
C
T
I
0
þ
2
:
303
Q
In
e
In
lf
In
C
T
I
0
ðA2:9Þ
¼
2
:
303
lC
T
I
0
Q
CaIn
e
CaIn
f
CaIn
þ Q
In
e
In
f
In
½
This shows that the total fluorescence depends on the intrinsic molecular
properties of In and CaIn and the relative abundance of the two forms:
F
T
/ Q
CaIn
e
CaIn
f
CaIn
þ Q
In
e
In
f
In
ðA2:10Þ
Moreover, because the product, Q
e
, is a composite measure of a molecule's ability
to absorb light and then emit fluorescence, we may think of Q
e
as the ''intrinsic
brightness'' of a fluorescent molecule. The brightness contribution of each indica-
tor form to the total fluorescence is weighted by the relative abundance of each
form. Finally, because f
CaIn
þ
f
In
¼
1, we can write
F
T
/ Q
CaIn
e
CaIn
f
CaIn
þ Q
In
e
In
1
ð
f
CaIn
Þ
ðA2:11Þ
References
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