Which of the following is NOT a benefit of quaternary structures over tertiary structures?

Quaternary structures, which consist of multiple polypeptide chains or subunits, offer several advantages over tertiary structures that are primarily focused on a single polypeptide. One of the key benefits of quaternary structures is their ability to regulate biological activity. The interaction between different subunits can lead to cooperative behavior, where the binding of a molecule to one subunit affects the binding properties of neighboring subunits. This is particularly important in allosteric regulation, where the conformational changes in one subunit can facilitate or inhibit the function of another.

Additionally, quaternary structures can enhance stability. The interactions between subunits often create a more robust and stable overall protein complex compared to that of a single polypeptide chain. This increased stability can provide a selective advantage in various biological environments.

Cooperativity is another significant benefit of quaternary structures as it allows for more efficient responses to changes in substrate concentration, often observed in enzymes that exhibit sigmoidal kinetics rather than hyperbolic kinetics typical of enzymes with only tertiary structures.

On the other hand, speed of catalysis is typically a characteristic more associated with the individual enzyme (or active site) of a protein rather than its quaternary organization. The catalytic efficiency mainly depends on