Enzyme kinetic kcat, kcat/Km - (Mar/16/2008 )
I have an enzyme, from my experiments, it has the following kinetic parameters.
Km 2.9 mg substrate/ml. [Substrate is starch, so mg is used rather than mol]
Vmax 3.5 mol product/L/min/mg protein [the product has very big MW value]
kcat 2349/s/mg protein
kcat/Km 810 ml/mg/s/ mg protein
A reviewer was asking: "the kcat and kcat/Km has excess significant figures". What does he meant of that?
He means that if you repeat this experiment, you will have very different results in the rightmost digit or two of the numbers. They are not significant, so should be rounded to avoid giving the impression of more accuracy than is really present in your measurement. Kcat of 2300 and Kcat/Km of 800 would be more appropriate.