Measurement of Cdk1/Cyclin B Kinase Activity by Specific Antibodies and Western Blotting.

Quantitative measurement of enzyme activity is a valuable approach to study how cells function. We present a method to measure the activity of the enzyme Cdk1/cyclin B. This enzyme is required by all eukaryotic cells to enter mitosis. Therefore, a biochemical assay to measure Cdk1/cyclin B activity can be used to identify cell populations that are in mitosis or to detect inhibitors of Cdk1/Cyclin B in vitro. A key distinction of the method presented here, compared to others, is that it uses a recombinant protein, a specific antibody, and a western blot apparatus, which makes the technique available to cell and molecular biology laboratories who do not wish to use radioisotopes, which are commonly required for other protein kinase assays.