Effects of Viscosity and Solvent Deuterium Identify Multiple Partially Rate-Limiting Steps in the Kinetics of Porcine Pepsin

  • Karen L. Rebholz
  • Dexter B. Northrop
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 306)


The mechanism of porcine pepsin and other aspartic proteinases has been studied for many years; however, the importance of diffusion of reactants to and from the enzyme has not been defined. We have now undertaken viscosity studies to examine the role of diffusion on the rate of catalysis by porcine pepsin. Also, isotope effects have been reported that are difficult to interpret within accepted kinetic mechanisms. Solvent deuterium isotope effect studies were undertaken to show the extent to which proton transfer affects the observed reaction rate and to determine at which step in the reaction proton transfer(s) occur.


Isotope Effect Aspartic Proteinase Reaction Proton Transfer Porcine Pepsin Observe Reaction Rate 
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Copyright information

© Plenum Press, New York 1991

Authors and Affiliations

  • Karen L. Rebholz
    • 1
  • Dexter B. Northrop
    • 1
  1. 1.Division of Pharmaceutical Biochemistry, School of PharmacyUniversity of WisconsinMadisonUSA

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