Abstract
Enzymology is a quantitative and exact science. Therefore it is important to understand how enzyme activity is measured and presented. A robust and reliable measure of the progress of an enzyme-catalyzed reaction is first and foremost requirement. Like with any other chemical reaction, progress of an enzyme-catalyzed reaction can be monitored either by the product formed (d[P]/dt) or by the substrate consumed (−d[A]/dt). The two rates are of course related by the reaction stoichiometry. It is desirable and often safe to follow the formation of product – a substance is better estimated when it is formed in a background where very little (or none) of it exists. On the other hand, to measure a decrease in the concentration of a reactant as it disappears – a small change in a large background – becomes daunting. In practice, a small decrease in substrate is relatively more difficult to observe than to follow a buildup of product from nothing. This is particularly relevant when we wish to record the initial rate (rate during very early time after the reaction is initiated, abbreviated as “v”), which is given by d[A]/dt when [P] ≈ 0. This is the rate at the beginning of the reaction or the instantaneous rate extrapolated to time zero.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Beame SL, Wolfenden R (1995) Glutamate γ-semialdehyde as a natural transition state analogue inhibitor of Escherichia coli glucosamine-6-phosphate synthase. Biochemistry 34:11515–11520
Haldane JBS (1965) Enzymes. MIT Press Classics (originally publisher, Longmans, Green, 1930)
Kornberg A (2000) Ten commandments: lessons from the enzymology of DNA replication. J Bacteriol 182:3613–3618
Sudarshana S, Noor S, Punekar NS (2001) On the importance of controls in enzyme assays – an odd example. BAMBEd 29:76–78
Suggested Reading
Bisswanger H (2014) Enzyme assays. Perspect Sci 1:41–55
Goddard J-P, Reymond J-L (2004) Recent advances in enzyme assays. Trends Biotechnol 22:363–370
Halling PJ, Gupta MN (2014) Measurement and reporting of data in applied biocatalysis. Perspect Sci 1(1–6):98–109
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer Nature Singapore Pte Ltd.
About this chapter
Cite this chapter
Punekar, N.S. (2018). Principles of Enzyme Assays. In: ENZYMES: Catalysis, Kinetics and Mechanisms. Springer, Singapore. https://doi.org/10.1007/978-981-13-0785-0_12
Download citation
DOI: https://doi.org/10.1007/978-981-13-0785-0_12
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-13-0784-3
Online ISBN: 978-981-13-0785-0
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)