Re: Statistical analysis possible for data relating pH and enzyme activity

Thomas,
 
The data you have is referred to as a pH-rate profile. The most common
types of statistical analysis of this type of data are to determine the pH
optimum of an enzyme, and, to find the inflection points of the profile. 
The inflection points are where the curvature changes from concave up to
concave down, or vice versa. If you have had calculus, you probably know
that such points are where the second derivative of the curve changes sign.
Such inflection points correspond to pKa values of residues, either on the
substrate or on the enzyme, that are being titrated.  The protonation state
of these residues affects the rate you observe.  

This is the same type of analysis one does with a standard titration curve,
in which one records the pH as a function of added acid or base.  The
inflection point gives the pKa of the substance being titrated.    

A web site that goes into the basics of the mathematical treatment of such
profiles can be found at: http://www.lsbu.ac.uk/biology/enztech/ph.html