Figure 3: The fluorescence emission spectra of HSA at 5-iodo-4-thio-2'-deoxyuridine various concentrations and an excitation wavelength of 282 nm in Tris-HCl butter solution (pH=7.4) at 27°C: Curve a, C (HSA) =6 μmol/L of the 5-iodo-4-thio-2'-deoxyuridine, curve b-h, the difference absorption spectrum between 5-iodo-4-thio-2'-deoxyuridin-HSA and 5-iodo-4-thio-2'-deoxyuridin, n (HSA) : n (4-SIdU) =1: 2, 4, 6, 8, 10, 12.