Allosteric Regulators and Covalent Modifications

These flashcards cover key concepts related to allosteric regulation, covalent modifications, and specific examples discussed in the lecture notes.

What is the purpose of allosteric regulation in enzymes?

Allosteric regulation rapidly influences enzyme activity, either increasing or decreasing it.

Which enzyme is known to be activated by fructose 1,6-bisphosphate?

Pyruvate kinase.

What role does AMP play in enzyme regulation?

AMP acts as an allosteric inhibitor, decreasing enzyme activity in low energy states.

What are the common types of covalent modifications discussed?

Phosphorylation, acetylation, and methylation.

Which amino acids are primary sites for phosphorylation?

Serine, threonine, and tyrosine.

What effect does histone acetylation have on DNA transcription?

It decreases the positive charge on histones, reducing DNA affinity and making it more transcriptionally active.

What happens to protein Z's activity if a phosphorylation site on tyrosine is mutated to glycine?

The activity of protein Z will be reduced due to the loss of the phosphorylation site.

What is the significance of S-Adenosyl methionine (SAM) in enzyme activity?

SAM is a common methyl donor that can influence enzyme activity through methylation.

How does the modification of serine to alanine affect hormone-sensitive lipase activity?

Removal of phosphorylation sites can significantly reduce enzyme activity, as seen in combination modifications.

What is the general effect of phosphorylation on an enzyme's activity?

Phosphorylation can either increase or decrease an enzyme's activity.