Besides cofactors,‭ ‬enzymes have inhibitors that slow or completely prevent enzymatic activity. Inhibitors change the enzyme kinematics by altering the rate of interaction between the enzyme-substrate complex or through the conformational change of the enzyme to prevent activity.

Enzymes are sensitive to the changes in the environment of the reaction. Changes in the pH or temperature can lower the effectiveness of the enzyme. The effectiveness of the enzyme is measured by how well a specific substrate can bind to its active site.  By altering the pH or the temperature,‭ ‬the enzyme can denature.  This denaturation is marked by a conformational change‭ (‬i.e. shape‭) ‬of the protein/active site and the substrate is no longer able to appropriately bind.

The highly unique structure of enzymes creates a high level of substrate specificity. Furthermore‭; ‬the large numbers of enzymes create many opportunities for regulation. The diversity of enzymes also allows for group specific enzymes that act on a general group of substrates such as a particular bond or functional group. However,‭ ‬all enzymes follow a quantitative method of description called the Michaelis-Menten kinetics. Enzyme kinetics is the quantitative description of enzyme behavior. The Michaelis-Menten equation describes the relationship between velocity‭ (‬rate of production of product‭) ‬and the substrate concentration

Through this relationship,‭ ‬the Michaelis constant‭ (‬Km‭) ‬and Vmax can be calculated graphically. Km is the point where velocity of the reaction is one-half the Vmax. The Vmax is the upper limit of the reaction. It is important to understand Km because it indirectly describes how‭ “‬effective‭” ‬the enzyme is in reaction. The smaller the Km value,‭ ‬the smaller the substrate concentration necessary to have an effective reaction.28‭ ‬If the Km value is large,‭ ‬a large concentration of substrate would be necessary to reach the same velocity as an enzyme with low Km. The Vmax is a useful tool in determining the likelihood of a reaction. In vivo,‭ ‬the Vmax is not an obtainable value,‭ ‬but this value can help determine the likely rate of reaction that is going to occur.

Plotting the substrate against the velocity does not produce an accurate value for important unknowns such as Km and Vmax. In order to construct a curve that assists in the determination of these unknowns,‭ ‬a Lineweaver-Burk plot is used. This plot and equation takes the hyperbolic relationship of the Michaelis-Menten equation and transforms it into a linear function.

The Lineweaver-Burk equation is a double-reciprocal plot with a y-intercept of‭ ‬1/Vmax and an x-intercept of‭ ‬-1/Km and the slope is Km/‭ ‬Vmax. The one weakness of the Lineweaver-Burk plot is that there is often a small amount of extrapolation necessary to determine the Km because that part of the curve extends to the negative region of the graph.

The importance of enzymatic reactions is that many times these chemicals that are undergoing reactions are part of cell’s mechanism for relating messages. Cellular messages can either be sent as chemical or electrical signals.