Define/differentiate

a. enzyme

b. active site

c. substrate

d. enzyme vs Isoenzyme

e. Cofactor vs Covalent Modulators vs Coenzyme

e. allosteric inhibition vs allosteric activation

Answers & Explanation:

a. Enzymes are each of the proteins produced by living beings, capable of accelerating chemical reactions related to vital functions. Each enzyme works in a specific way, always acting on a given compound, always in the same reaction.

b. The active site is a substrate-specific (each one has a different format) molecule to which the enzyme can bind. And for that, both the substrate and the enzyme can change their structures, fitting perfectly as if they were lock and key.

c. Substrate is the compound on which the enzyme performs its function. The specific binding between an enzyme and a substrate is related to the three-dimensional form of both substances.

d. Enzymes are proteins that accelerate reactions, decreasing the amount of energy needed for that specific reaction.

Isoenzymes are multiple forms of an enzyme molecule, capable of catalyzing the same reaction.

e. Some enzymes do not work on their own and need a cofactor, a substance needed to activate an enzyme.

The binding between cofactor and enzyme is temporary, and when they are not bound, the enzyme becomes inactive. The cofactors may be organic (such as vitamins) or inorganic (minerals such as zinc, magnesium and calcium).

Coenzymes are non-protein organic substances essential for the functioning of some enzymes.

Many vitamins, for example, are important because they are coenzymes in vital processes, such as coenzyme A, important for the cellular respiration.

Covalent modulation occurs when there is covalent modification of the molecules of an enzyme, with conversion between active/inactive forms.

f. After the onset of enzyme activity begins, the high concentration of ATP (adenosine triphosphate) acts as a signal to inhibit enzyme activity from accelerating reactions.

When the enzyme action continues, the ATP concentration drops, and this feedback system sends the signal again, but this time to the activators, starting the enzymatic activity again.