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dependent on hemolytic effect. Figure 2 presents time course of erythrocyte hemolysis
(Ȗ = extent of hemolysis), which were obtained at equimolar concentration (4 × 10
-5
M) of studied complexes. As individual kinetic characteristic of hemolytic activity of
each complex the duration of induction period of hemolysis was used. The duration of
induction period was defined as a time of reaching of the extent of hemolysis of 0.1
(dash line). The induction time corresponding each of studied complexes are showed
on inset of Figure 2.
FIGURE 2
Hemolysis of erythrocytes under of SNICs.
Having carried out the hemolytic experiments we often visually observed the color
change preceding to beginning of hemolysis. It might indicate to the chemical pro-
cesses occurred inside of cell. Spectrophotometric investigation of hemolysates re-
vealed the typical pattern of the hemoglobin spectral change suggesting on oxidation
of oxyhemoglobin to methemoglobin (inset, Figure 3).
Obviously, it arises from interaction of NO penetrating into cell with oxyhemoglo-
bin. To investigate the time course of methemoglobin formation we took out the ali-
quots of erythrocyte suspension then quickly destroyed the cells by distilled water and
determined the methemoglobin content by the absorbance measurements at 630 nm.
Figure 3 shows time course of methemoglobin formation inside of erythrocytes under
exposure to Cys and Pym. It is clear that the methemoglobin formation in presence of
each SNIC proceed with different rate. In addition it was established that kinetics of
methemoglobin formation followed to the ¿ rst order equation:
(3)
[
HbFe
3
+
]
=
[
HbFe
3
+
]
⋅
(
−
e
−
t
)
∞
Therefore, the first order rate constants were determined (Figure 3, inset). It is clear
that obtained rate constants differ almost in order of quantity.
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