核糖核酸与甲基紫作用机理及含量测定的研究

研究了在pH 6.0的伯瑞坦-罗比森弱酸性缓冲溶液中，小分子甲基紫与生物大分子核糖核酸之间发生强烈静电缔合相互作用，引起分子光谱红移，吸收值变小。甲基紫在最大吸收波长558 nm处的吸收峰强度显著下降，下降程度与核糖核酸的含量呈线性关系，应用光谱法研究了反应体系酸度、甲基紫用量、反应时间对反应速度的影响，确定了试验最佳条件，提出并建立了测定痕量核糖核酸含量的新方法。线性范围为1.0～8.0 μg·mL-1, 检测限为0.52 μg·mL-1，相关系数r为0.999 9，该法简便，快速，具有较高的选择性和灵敏度，对合成样品中核糖核酸的测定令人满意;初步探讨了反应机理，认为，甲基紫分子与凝聚在RNA分子链上的反离子之间发生静电缔合作用，然后，以协同方式与RNA分子发生键合，使甲基紫三苯环平面结构受到破坏，π-电子叠合程度降低，吸收值降低，最大吸收波长红移。

Studies on the Interaction between RNA with Methyl Violet and Determination of RNA by Spectrophotometry

An analytical method for the determination of ribonucleic acid was established by spectrophotometry. At maximum absorption wavelength for methyl violet in the B-R buffer solution, and under the best conditions, the degree of decrease of the absorbance was linear with the amount of ribonucleic Acid. It was a new and preferable approach for the determination of ribonucleic Acids. The method with the linearity range was 1.0 to 8.0 microg x mL(-1) and the detection limit was 0.52 microg x mL(-1), and the correlation coeffient was 0.9999. This method was simple, rapid, and selective. So it was satisfactory to the application for the determination of ribonucleic Acid. The reaction mechanism was electrostatic interaction to make molecular association of RNA with methyl violet, to go on antiion permutation and bonded reaction of concert.