Classify each phrase as describing a competitive inhibitor, uncompetitive inhibitor, or mixed (mixed noncompetitive) inhibitor. Note that K m refers to apparent K m.

Mixed inhibition refers to the combination of two reversible types of enzyme inhibition, competitive inhibition and non-competitive inhibition. The term mixed is used when the inhibitor can bind both the free enzyme and the enzyme-substrate complex. In mixed inhibition the inhibitor is in a different place from the active site where the substrate is found.

Mathematically, mixed inhibition occurs when both alpha and alpha-prime factors (introduced in the Michaelis-Menten equation representing competitive and non-competitive inhibition respectively) are present (they are larger than unity).

In a special case of mixed inhibition, the alpha and alpha-prime factors are the same, then non-competitive inhibition occurs.

With this type of inhibition Km depends on the affinity of the inhibitor to join E or ES and Vmax decreases.

Enzymatic inhibitors are molecules that bind enzymes and decrease their activity. Since blocking an enzyme can kill a pathogen or correct a metabolic imbalance, many medications act as enzyme inhibitors. They are also used as herbicides and pesticides. However, not all molecules that bind to enzymes are inhibitors; Enzymatic activators bind to enzymes and increase their activity.

The binding of an inhibitor can prevent the substrate from entering the active site of the enzyme and / or hinder the enzyme from catalyzing its corresponding reaction. The inhibitor binding may be reversible or irreversible. Normally, irreversible inhibitors react with the enzyme covalently and modify their chemical structure to the level of essential residues necessary for enzymatic activity. In contrast, reversible inhibitors bind to the enzyme in a non-covalent manner, resulting in different types of inhibitions, determined whether the inhibitor binds to the enzyme, the enzyme-substrate complex or both.

Many medications are enzymatic inhibitors, so their discovery and improvement is an active field of research in biochemistry and pharmacology. The validity of a medicinal enzyme inhibitor is usually determined by its specificity (its inability to bind to other proteins) and its potency (its dissociation constant, which indicates the concentration necessary to inhibit an enzyme). A high specificity and potency ensures that the medication will have few side effects and therefore a low toxicity.