Gryczynski I, Johnson M L, Lakowicz J R
University of Maryland School of Medicine, Department of Biological Chemistry, Baltimore 21201.
Biophys Chem. 1988 Sep;31(3):269-74. doi: 10.1016/0301-4622(88)80032-2.
Acrylamide was found to be an effective quencher of Yt-base (Y-4,9-dihydro-4,6-dimethyl-9-oxo-1H-imidazo-1,2a-purine) in water. In the absence of collisional quenching the decay of Yt-base in water is predominantly a single exponential. The intensity decays become increasingly heterogeneous when quenched by acrylamide. The frequency-domain data were analyzed using the radiation model, which provides estimates of molecular parameters characteristic of the system. The mutual diffusion coefficient at 20 degrees C was found to be 0.5 x 10(5) cm2/s, the Yt-base acrylamide interaction radius was 8 A, and the rate constant for quenching was 100 cm/s. These values indicate that quenching is diffusion-limited, i.e., the encounter complex is deactivated at least 2-fold faster than the rate of diffusive encounters.
已发现丙烯酰胺是水中Yt碱基（Y - 4,9 - 二氢 - 4,6 - 二甲基 - 9 - 氧代 - 1H - 咪唑并[1,2 - a]嘌呤）的有效猝灭剂。在没有碰撞猝灭的情况下，Yt碱基在水中的衰减主要是单指数形式。当被丙烯酰胺猝灭时，强度衰减变得越来越不均匀。使用辐射模型对频域数据进行了分析，该模型提供了系统特征分子参数的估计值。发现在20摄氏度时的互扩散系数为0.5×10⁵ cm²/s，Yt碱基 - 丙烯酰胺相互作用半径为8 Å，猝灭速率常数为100 cm/s。这些值表明猝灭是扩散受限的，即遭遇复合物失活的速度至少比扩散遭遇速率快2倍。
