Are there still people who believe that enzyme kinetics is a knotty discipline? This website, dedicated to the kinetics of enzyme-modifier interactions, aims at loosing any remaining knots in the classification and analysis of inhibition and activation mechanisms. The term modifier indicates any kind of  inhibitor or activator of the enzyme’s activity. All topics discussed here are based on a more comprehensive treatment published by Springer [1]. Since some concepts are new and cannot be found elsewhere, in the following pages reference will be made to this book specifying the appropriate chapters or pages.

The control of enzyme activity is a primary theme in biochemistry, physiology, pharmacology and related disciplines. Therefore, the topics discussed herein are addressed to studentsteachers and researchers in academia and industry interested in a field that necessitates systematization.

Traditionally, enzyme inhibitors are subdivided in the categories competitive, uncompetitive and mixed inhibition. Notably, the term noncompetitive inhibition has been discouraged for all purposes with the exception of  pure noncompetitive inhibition [2]. Unfortunately, the terms mixed and noncompetitive continue to be used interchangeably to designate different mechanisms, with confusion concerning both nomenclature and mechanistic issues. However, nobody can be criticized for any inadequate name attached to otherwise sound results because no new instructions have been released by authorities after the appearance of the fist recommendations [2].

The notion that any nonfibrous protein may theoretically be allosteric is opening new lanes in targeted enzyme regulation [3]. Thus, contemporary studies of enzyme inhibition and activation can benefit from methods that are not at risk of overlooking essential information, such as the kinetic mechanism of allosteric modifiers. Reluctance in accepting novel approaches in favor of obsolete methods is mainly bound to tradition and lack of information. Nevertheless, the correct assignment of kinetic mechanisms is a prerequisite for interpreting physiological processes in metabolic networks. Similarly, this information can support and fuel drug design and new pharmacological applications.

How to citeReferences, equations and figuresDocuments and imagesThanks
Any information from this website should be acknowledged by citing the URL and/or the book:
Baici A (2015) Kinetics of Enzyme-Modifier Interactions – Selected Topics in the Theory and Diagnosis of Inhibition and Activation Mechanisms. Springer, Vienna.
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It would be impossible to maintain this website without the precious and very competent help of two dear friends at the Department of Biochemistry, University of Zurich:
Steve Rast, Head IT Service
Dr. Stefan Klauser, Former Head IT Service

Thank you very much Stefan and Steve!

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Last updated: December 4, 2023


  1. Baici A (2015) Kinetics of Enzyme-Modifier Interactions – Selected Topics in the Theory and Diagnosis of Inhibition and Activation Mechanisms. Springer, Vienna
  2. Nomenclature Committee of the International Union of Biochemistry (1982) Symbolism and terminology in enzyme kinetics. Recommendations 1981. Eur J Biochem 128: 281-291. Electronic version available
  3. Gunasekaran K, Ma B, Nussinov R (2004) Is allostery an intrinsic property of all dynamic proteins? Proteins 57: 433-443

Images: Knotted columns in the San Vigilio Cathedral, Trento, Italy (originals by Antonio Baici, 2013).
In italiano: Cattedrale di San Vigilio, Trento, colonne ofitiche nel protiro meridionale del transetto.