Kazantsev A V, Maksakova G A, Fedorova O S
Bioorg Khim. 1995 Oct;21(10):767-73.
Kinetics of photomodification of 26-meric deoxyribonucleotide pTTGCCTTGAATGGGAA-GAGGGTCATT with derivatives of the complementary oligonucleotides pTCTTCCCATTC, pTCTTCCCA, and pTTCCCA bearing a residue of (p-azidotetrafluorobenzoyl)aminopropylamine(-ArN3) attached to the terminal phosphate (reagents I, II, and III, respectively) was studied at 37 degrees C. It was established that during irradiation the reagents are inactivated, loosing their affinity to the target. A kinetic equation describing the modification was suggested. From the dependence of the time-limited modification level on the reagent concentration, the association constants of the reagents with the target were determined: [Kx = (9.9 +/- 0.4) x 10(4), (1.1 +/- 0.1) x 10(5), and (8.4 +/- 2.1) x 10(6) M-1 for reagents I, II, and III, respectively] and the efficiency of the modification in the complex gamma ef (ca. 0.3 for all the reagents) were determined. From the dependence of the modification level [PZ]/p0 on time for reagent II, the rate constant was determined for the rate-determining step of the photomodification k0 = (7.9 +/- 0.9) x 10(-3) s-1, which is close to the rate constant for the photolysis of p-azidotetrafluorobenzoic acid kp = (5.5 +/- 0.3) x 10(-3) s-1.
在37℃下研究了26聚体脱氧核糖核苷酸pTTGCCTTGAATGGGAA - GAGGGTCATT与互补寡核苷酸pTCTTCCCATTC、pTCTTCCCA和pTTCCCA的衍生物（分别为试剂I、II和III）的光修饰动力学，这些衍生物在末端磷酸上连接有(p - 叠氮基四氟苯甲酰)氨基丙胺(-ArN₃)残基。结果表明，在辐照过程中试剂失活，失去了对靶标的亲和力。提出了一个描述修饰过程的动力学方程。根据限时修饰水平对试剂浓度的依赖性，确定了试剂与靶标的缔合常数：[试剂I、II和III的Kx分别为(9.9 ± 0.4)×10⁴、(1.1 ± 0.1)×10⁵和(8.4 ± 2.1)×10⁶ M⁻¹]，并确定了复合物中修饰效率γef（所有试剂约为0.3）。根据试剂II的修饰水平[PZ]/p₀对时间的依赖性，确定了光修饰速率决定步骤的速率常数k₀ = (7.9 ± 0.9)×10⁻³ s⁻¹，这与对叠氮基四氟苯甲酸光解的速率常数kp = (5.5 ± 0.3)×10⁻³ s⁻¹相近。
