BIOL: Lecture Notes- Sept.24: Enzymes: Active Site, Regulation, and Function

Enzymes' active sites often have positive charges to stabilize or modify substrates.
A positive active site attracts negatively charged molecules.
Enzymes function best under ideal conditions, including optimal temperature and pH (ideal environment).

Enzymes have an optimal temperature where they function most efficiently.
Slight deviations from optimal temperature can reduce enzyme activity; significant deviations (higher or lower) impair function (e.g., fever in humans).
Cofactors (inorganics like zinc, copper, iron) and coenzymes (organics like vitamins, e.g., coenzyme A) assist enzymes in reactions.

Enzyme Inhibitors can stop enzyme function:
- Competitive inhibitors bind to the active site, blocking the substrate.
- Noncompetitive inhibitors bind to a different site, altering the active site's shape.
Allosteric regulation turns enzymes on or off by changing their shape.
Cooperativity is a type of allosteric regulation where binding at one site increases the affinity for subsequent binding events at other sites (e.g., hemoglobin's oxygen binding).

Membranes can produce gradients using pumps, such as the Sodium-Potassium ( $Na^+$ / $K^+$ ) pump.