Question

Antibotics have been useful in determining whether cellular events depend on transcription or translation. For example, actinomycin D is used to block transcription, and cycloheximide (in eukaryotes) is used to block translation. In some cases, though, surprising results are obtained after antibiotics are administered. Adding actinomycin D, for example, may result in an increase, not a decrease, in the activity of a particular enzyme. Discuss how this result might come about

Answer 1

actinomycin D may also act to block transcription of inhibitors of the enzyme's activity

Step-by-step explanation:

Enzyme inhibitors are molecules that are able to interact with enzymes and enzymatic complexes in order to reduce or block enzymatic activity. There are many genes that encode enzyme inhibitors. For example, in yeast (Saccharomyces cerevisiae), the PHO81 gene encodes a protein (Phosphate system positive regulatory protein) that inhibits the function of the cyclin/CDK complex, which is an enzymatic complex that acts to regulate progression through the cell cycle. In the example above described, actinomycin D could block transcription of an enzymatic inhibitor, which would lead to an increase of the enzymatic activity.