Number of permease enzymes required for transition to the fully induced state

Range >300 molecules/cell
Organism Bacteria Escherichia coli
Reference Li GW, Xie XS. Central dogma at the single-molecule level in living cells. Nature. 2011 Jul 20 475(7356):308-15. doi: 10.1038/nature10315. p.313 cation of fig.5d and p.314 left column 2nd paragraphPubMed ID21776076
Primary Source Choi PJ, Cai L, Frieda K, Xie XS. A stochastic single-molecule event triggers phenotype switching of a bacterial cell. Science. 2008 Oct 17 322(5900):442-6. doi: 10.1126/science.1161427.PubMed ID18927393
Method "Advanced single-cell fluorescence microscopy"
Comments "A large expression burst of LacY (~300 molecules) is necessary to trigger the switching, which results from the complete dissociation of a single transcription factor, LacI, from DNA. This experiment shows that a low-probability, singlemolecule stochastic event can determine cell fate...With single-molecule imaging, uninduced E. coli cells have been shown to contain 0–10 copies of the permease enzyme, which is below the threshold for positive feedback (more than 300 molecules per cell)(primary source). Transition to the fully induced state therefore requires a large burst of protein synthesis (Fig. 5d)."
Entered by Uri M
ID 109956