a 53,000-dalton protein ( p53 ) present in large amounts in several types of tumorigenic cells was rapidly degraded in nontumorigenic balb/c 3t3 fibroblasts ( t 1/2 , approximately 0.5 h ) but not in tumorigenic methylcholanthrene-induced mouse sarcoma cells ( t 1/2 , greater than 2 h ) .
C0016030
fibroblasts
C0007634
cells