Origin lab version 8

With the
help of a tryptophan emission-quenching experiment, we detected the
interaction of the complexes with protein BSA.^{45 (link),46 (link)} Initially, 2 × 10^–6 M BSA solution was prepared
in Tris-HCl/NaCl buffer. Then, aqueous solutions of the complexes
were added to BSA solution with a regular increase in their concentrations.
After each addition, the solutions were shaken slowly for 5 min, and
the fluorescence at a wavelength of 295 nm (λ_ex =
295 nm) was recorded. A decrease in the fluorescence intensity of
BSA at λ = 340 nm was observed upon increasing the concentration
of the complex due to the interaction between the complex and BSA.
With the help of the Stern–Volmer eq vii, we quantitatively determine the quenching
constant (K_BSA). We obtained a linear
plot of I₀/Ivs [complex] using eq vii with the help of Origin Lab, version 8.5. where I₀ is the
fluorescence intensity of BSA in the absence of the complex, I is the fluorescence intensity of BSA in the presence of
a complex of concentration [Q], τ₀ is the lifetime of tryptophan in BSA (found as 1 × 10^–8), and k_q is the quenching constant. Equation viii gives the binding
properties of the complexes. where K is the binding constant
and n is the number of binding sites.

In total, 3–5 independent replicates were conducted for all experiments. The results are expressed as the mean ± SD. The Student's t test with a significance level of P<0.05 was used to calculate statistically significant differences. OriginLab version 8.5 software (OriginLab, Northampton, MA, USA) was used to analyze the experimental data.