Three groups of drugs are used to reduce the stickiness of platelets, thus preventing platelets from clumping together to form platelet plugs. The anti-platelet drugs are most effective in preventing abnormal blood clots from forming in arteries (as opposed to veins). Aspirin and dipyridamoleâ (Aggrenox).
In order to react, colliding molecules must have a total kinetic energy equal to or greater than some minimum value [Figure 14.13(b)]. The minimum energy required to initiate a chemical reaction is called the activation energy, Ea. The value of Ea varies from reaction to reaction.
Enzymes. Enzymes are proteins, produced by living cells; they catalyze chemical reactions by lowering the activation energy. Activation energy is the energy required for a chemical reaction to occur. Enzymes are generally globular proteins with characteristic three-dimensional shapes.The active site is the binding site for the enzymeâs substrate. Enzymes are specific for substrate molecules.ctivation energy is the energy required for a chemical reaction to occur. Enzymes are generally globular proteins with characteristic three-dimensional shapes. The active site is the binding site for the enzymeâs substrate. Enzymes are specific for substrate molecules.