What is the Difference Between Continuous Assay and Stopped Assay?

The difference between continuous assay and stopped assay lies in the sampling method and the rate of reaction measurements. Here are the main differences:

• Continuous Assay: In this analytical method, readings are taken continuously without stopping or holding the reaction. The assay provides a continuous reading of activity, and the course of the reaction is continually followed until completion. Examples of continuous assays include spectrophotometry, calorimetry, chemiluminescence, and fluorimetry. These methods measure the progress of reactions by light or heat, and are typically easier to perform and provide real-time data.
• Stopped Assay: Also known as a discontinuous assay, this method involves taking readings at intervals by stopping the reaction. Samples are taken from the enzyme reaction at set intervals, and the amount of substrate consumed or product formed is measured. Stopped assays provide only one measure point, and the velocity is derived from the slope of a line connecting this point with the blank at the start of the reaction. Examples of stopped assays include radiometric assays.

In summary, continuous assays measure the rate of reaction continuously, while stopped assays measure the rate of reaction at specific intervals. Continuous assays are generally more convenient and easier to perform, providing real-time data on the reaction.

Comparative Table: Continuous Assay vs Stopped Assay

Here is a table comparing continuous assay and stopped assay:

Continuous assays measure the progress of reactions continuously until completion, providing real-time data on enzyme activity and reaction kinetics. In contrast, stopped assays are performed by taking samples at set intervals, which can result in an incomplete understanding of the reaction rate changes.