脱氧核糖核酸变性和损伤的吸附伏安法研究

本文用汞电极（ＨＭＤＥ）二次导数阴极吸附伏安（ＳＤ－ＡｄＣＳＶ）和碳电极（ＧＣＥ、ＣＰＥ）导数循环伏安（ＦＤ－ＣＶ）法研究了核酸受热、紫外线、超声波和丝裂霉素Ｃ（ＭＭＣ）作用下的变性作用。在０．１ｍｏｌ／Ｌ（Ｋ２ＨＰＯ４＋ＫＨ２ＰＯ４）－０．１ｍｏｌ．Ｌ ＮａＣｌ（ｐＨ７．０）底液中，吸附的单股（ｓｓ－）和双螺旋（ｄｓ－）ＤＮＡ分别在ＨＭＤＥ上得到特征还原峰Ｐ３和Ｐ２，和在碳电极上得到氧化峰Ａ。物

Study on Denaturation and Damage in Native Deoxyribonucleic Acid by Differential Adsorptive Stripping Voltammetry

Denaturation and damage in matuve DNA (RNA) by therrnal action, ultrasonication, UV-irradiarion and antitumor agent mitomycin C (MMC) actions were studied by means of cathodic/anodic adsorptive stripping voltammetry using second-order differential voltammetric and differential cyclic voltammetric models in combination with HMDE, GCE and CPE electrodes. In the background electrolyte consisted of 0.1 mol/L (K2HPO4+ KH2PO4) -0.1 mol/L NaCl (pH 7.0),the adsorbed double-helical (ds-) and single-strandes (ss-) DNA on HN1DE produce one of their specific reduction peak at P,2-1. 37 V vs. Ag/AgCl, ds-) and P3( -1.56 V. s DNA), respectively, and two oxidation peaks of A (+1. 08 V) and G ( +0.78 V) to. both of adsorbed DNA species on GCF and CPE. When the native DNA was damaged by physical or chemical agents. the voltammogramchanged not only in peak currents. but also in forms and parameters. All of the changes in voltammogram indicated that the double helix DNA might be defected in a certain extent in comformaticn. Reduced MMC must combine with ss-NNA prior to intercolate into or crosslink to ds-DNA by incubation in physiological conditions, since P3 disappeared before p2 on the voltamrnogram. This method may be applied conveliiently to probing the damage in native DNA in vitro.