Association constant of lac repressor to operator

Value 7e+9 M^-1×Sec^-1
Organism Bacteria Escherichia coli
Reference Riggs AD, Bourgeois S, Cohn M. The lac repressor-operator interaction. 3. Kinetic studies. J Mol Biol. 1970 Nov 1453(3):401-17 abstract, p.408 top paragraph & p.413 3rd paragraphPubMed ID4924006
Method Abstract p.401: "A sensitive membrane filter assay for the lac repressor-operator complex has been used to study the kinetics of repressor and operator interaction."
Comments Abstract p.401: "The rate of association of repressor and operator is very fast and follows second-order kinetics with the rate constant for association (ka) being 7 × 10^9 M^-1 sec^-1 in [researchers'] standard buffer." P.408 top paragraph: "The determination of ka from [researchers'] kinetic experiments should, therefore, be quite accurate. The data shown in Figure 5 lead to a ka value estimate of 7×10^9 M^-1×Sec^-1." P.413 3rd paragraph: "The rate of association of R and 0 is very fast. Kinetics appropriate for a simple bimolecular reaction are followed with ka = 7×10^9 M^-1×sec^-1 in [investigators'] standard buffer."
Entered by Uri M
ID 104607