MMfit program fits initial rate data for enzyme catalyzed reactions to the equation below using the method of Wilkinson, G.N. (1961) Biochem. J. 80, 324-332. kcat(obs)=kcat So/(So+Km)
kcat(obs) is obtained by dividing d[P] / dt by the enzyme concentration. If the enzyme concentration is not known then enter the initial rates "v" or d[P] / dt instead of kcat(obs). In this case it will output values for Vmax, Km and Vm/Km.
When fitting without estimates, a linear Lineweaver-Burke plot is used to make the initial estimate of kcat and Km. In this case usually, one iteration usually gives the best fit.
If the initial Lineweaver-Burke plot does not give good estimates of kcat and Km you can enter your own estimates and then fit using your own estimates of kcat and Km. Doing more iterations does not necessarily improve the fit obtained.
Results can printed, saved as a text document or copied and pasted into other applications such as Word.
MMfit application also provides instructions and test data.
You may also be interested in the iPhone app EnzymeQA as it contains key facts in enzymology and should help you check you have used the appropriate conditions for determining catalytic constants. NOTE: MMfit can only be purchased via the Mac App Store (the buy link redirects you to its App Store page). To purchase/download applications via the App Store an Apple account is required.
What`s New in This Release: [ read full changelog ]
· The user interface has been improved. Some bugs have been detected and fixed.
