Instead of having a ridged substrate molecule that will only fit into a specific active site, we have an active site that can stretch to accept a range of molecular shapes for the substrate analogous to how gloves stretch to fit more than one size hand. This model explains more adequately how active site blockers can block the active site and inhibit the enzyme molecule. These are molecules that attach themselves to other parts of the apoenzyme away from the active site. However, when the inhibitor bonds to the enzyme molecule, it alters the shape, and therefore, the shape of the active site is altered so that the active site will no longer accept a legitimate substrate molecule. There are three factors that will alter the activity of an enzyme.
Every enzyme has a temperature range in which the enzyme can function within.
Usually on the low end of that range the enzyme has low activity. Near the middle part of the range, the activity of the enzyme increases to a maximum called the optimum temperature. Outside that range, the enzyme ceases to function as a catalyst. If a human becomes hypothermic with a abnormally low body temperature, then enzymes cease to function and biochemical reactions within the cells begin to shut down. If the human becomes hyperthermic with an abnormally high body temperature, then the enzymes activity drops rapidly, and the reactions of the cells begin to shut down once again.