MadSci Network: Biochemistry |
Tessa, Yes, indeed, it is possible to experimentally determine numerical, quantitative descriptions of enzymatic activity. This general area of study is called enzyme kinetics, and it is a branch of chemical kinetics, which is the study of rates and mechanisms of chemical reactions. The essential mathematical description of enzyme kinetics is called the Michaelis-Menten equation, which relates the rate of an enzymatic reaction to the concentration of the substrate (the reactant that the enzyme captures and performs chemistry on). As the concentration of the substrate increases, the rate of conversion of substrate to product increases until the enzyme, which is present in very small concentrations compared to that of the substrate, become saturated. Further concentrations of the substrate do not result in any increase in rate, since all of the enzyme molecules are already capturing substrate and converting it into product as their maximum rate. This rate is called the maximum rate, or Vmax. If you can find a graduate-level biochemistry textbook, it will have a section on enzyme kinetics. Here are couple of web sites that also cover this important area: http://dept.physics.upenn.edu/courses/gladney/mathphys/subsection4_1_6.html (has a description of the origin of enzyme kinetics, and how the Michaelis- Menten equation is derived) http://jeffline.tju.edu/CWIS/DEPT/biochemistry/kinetics/HTML/PAGE3A.HTML (another, somewhat simpler, description of enzyme kinetics)
Try the links in the MadSci Library for more information on Biochemistry.