p53 (wild type) (human), (recombinant)

The p53 protein is a transcription factor that plays a crucial role as a tumor suppressor. In normal cells, p53 levels are kept low by degradation mediated by MDM2. In response to stress such as DNA damage and hypoxia, wild-type p53 activates genes that lead to cell cycle arrest and, in the event of severe stress, to apoptosis. The importance of p53 is illustrated by the presence of p53 mutants in 50% of all human cancers. When p53 is inactivated by either mutation or deletion, cells become increasingly vulnerable to malignant transformation. Mutations in p53 lead to a conformational change in protein structure which results in increased stability of the protein. Consequently, p53 is frequently found in higher levels in malignant cells than in normal cells.