A steady-state absorption and emission spectroscopy was used to create a comprehensive work and to study the interaction of the wild type Escherichia coli purine nucleoside phosphorylase and its mutants, PNPF159Y and PNPF159A, with a potent E. coli PNP inhibitor - formycin A. The absorption and emission spectra were recorded in the presence and absence of the phosphate at the 50 mM concentration. From the collected sets of data dissociation constants (K_d), apparent dissociation constants (K_app) and Hill's coefficients (h) were calculated. Additionally, the temperature dependence of the enzymes emission quenching at two temperatures, 10 °C and 25 °C, was examined. To verify the calculations, total difference absorption spectra were computed for all types of the complexes. A prominent quenching of the PNPF159Y emission indicates a complex formation, with the strongest association in the phosphate buffer, pH 7, relative to the wild type enzyme. On the other hand, results testify to a deterioration of the interactions in the E. coli PNP/PNPF159Y and formycin A complexes in the presence of the phosphate, pH 8.3. Moreover, data obtained for the PNPF159A-FA complexes confirm a weak association of the FA to the mutant's active center.

稳态吸收和发射光谱用于开展全面的研究工作，并研究野生型大肠杆菌嘌呤核苷磷酸化酶及其突变体PNPF159Y和PNPF159A与有效的大肠杆菌PNP抑制剂-甲霉素A的相互作用。在存在和不存在浓度为50 mM的磷酸盐的情况下记录吸收光谱和发射光谱。从收集的数据解离常数（K _d），表观解离常数（K _app）和希尔系数（h）进行了计算。另外，检查了在两个温度（10°C和25°C）下酶发射猝灭的温度依赖性。为了验证计算结果，计算了所有类型配合物的总差吸收光谱。相对于野生型酶，PNPF159Y发射的显着淬灭表明形成复杂的复合物，在磷酸盐缓冲液pH 7中具有最强的缔合。另一方面，结果证明在存在磷酸盐（pH 8.3）的情况下，大肠杆菌PNP / PNPF159Y和甲霉素A配合物之间的相互作用会变差。此外，从PNPF159A-FA复合物获得的数据证实了FA与突变体的活性中心之间的弱关联。