enzyme assays types

1. Enzyme assays

2. Methods to assay enzymes
Introduction:
• Assay is an act of analyzing test or appraisal to determine
the components of a substance or object. • Enzyme assays
are laboratory methods for measuring enzymatic activity. •
They are vital for the study of enzyme kinetics and enzyme
inhibition. • The assay is the act of measuring how fast a
given (unknown) amount of enzyme will convert substrate
to product (the act of measuring a velocity). • Enzyme
assays measure either the disappearance of substrate over
time or the appearance of product over time.

3. Types of Enzyme assay Two types (Based on sampling methods) 1.
Continuous assays Continuous assays are most convenient, with one
assay giving the rate of reaction with no further work necessary. It
gives a continuous reading of activity, multiple measurements, usually
of absorbance change are made during the reaction either at specific
time intervals (usually every 30 or 60 seconds) or continuously by a
continuous- recording spectrophotometer. A few methods are
spectrophotoometric, fluorometric, calorimetric and chemi-
luminescent.

4. Discontinuous assays: In this assay where the samples
are taken, the reaction stopped and then the
concentration of substrates/products determined. The
discontinuous assays are radiometric and
chromatographic.
Features of a good Enzyme assay • Simple and Specific •
Rapid (one doesn’t need to wait for hrs or weeks for the
results to appear) • Sensitive ( very little sample) • Easy
to use • Economical
Measurement of enzyme activity by spectroscopy