Nutlin-3b ((+)-Nutlin-3) is a p53/MDM2 antagonist or inhibitor (IC50: 13.6 μM), 150-fold less potent (+)-enantiomer of Nutlin-3 as in comparison with opposite (-)-enantiomer Nutlin-3a.

MDM2:13.6 μM

Nutlin-3b 作为非MDM2相关细胞活动的负控制物质有其应用价值。Nutlin-3a 仅在带有野生型p53的细胞中诱导MDM2和p21的表达（但不是p53）。而Nutlin-3b 不论细胞的p53状态如何都无效果。仅有活性异构体Nutlin-3a 显示出强大的抗增殖活性，并在带有野生型p53的细胞与带有突变型p53的细胞之间明确分离出效力差异。Nutlin-3b 在野生型p53细胞中的效力显著低于对突变型p53细胞的Nutlin-3a 的效力。经过48小时暴露于Nutlin-3a 之后，45%的细胞群体变为TUNEL阳性，但用Nutlin-3b 处理的细胞与未处理的对照组无异。[1]

Biacore study: Competition assay is performed on a Biacore S51. A Series S Sensor chip CM5 is utilized for the immobilization of a PentaHis antibody for capture of the His-tagged p53. The level of capture is ~200 response units (1 response unit corresponds to 1 pg of protein per mm 2). The concentration of MDM2 protein is kept constant at 300 nM. Nutlin-3 is dissolved in DMSO at 10 mM and further diluted to make a concentration series of Nutlin-3 in each MDM2 test sample. The assay is run at 25°C in running buffer (10 mM Hepes, 0.15 M NaCl, 2% DMSO). MDM2-p53 binding in the presence of Nutlin-3 is calculated as a percentage of binding in the absence of Nutlin-3 and IC50 is calculated

MTT assay(Only for Reference)