What are enzymes and what is their function?
Enzymes are protein molecules that play an important role: allow chemical reactions to occur in living beings , and also in environments near where they develop.
Enzymes act as anchor matrices for the compounds that have to be processed (called “substrates”), which are modified to produce new compounds, called “products.”
Enzymes manage to accelerate the speed of numerous reactions , which otherwise could not be achieved under the ordinary conditions of living beings.
The proteins are formed by numerous amino acids, which are grouped through peptide bonds , forming long chains. These chains usually form spirals, curls and folds.
That is why enzymes adopt a characteristic structure that is very important when exercising their catalytic function. In general, enzymes are globular proteins .
Enzymes in general have a high substrate specificity , which means they can “recognize” the chemical compound they must process and anchor it in what is known as an “active site.” The substrate “fits” in said active site, just as a key fits in the design of a lock. Sometimes, very similar compounds can be inserted in the same active site, this is called “competitive inhibition” of a reaction.
If we consider the structure of the cell , some enzymes are located in the cytosol , others in plasma s membranes , others in certain organelles (example: mitochondria, peroxisomes, chloroplasts) , although there are also enzymes that can be located in different structures.
It is also worth clarifying that some enzymes are released out of the cell (extracellular), while others always remain inside those (intracellular).
Different optimal conditions
Enzymes are usually active in a certain range of temperature and pH conditions , with an optimum where their reaction speed is maximum. Most enzymes in the human body work well at 36-37 ° C, which is body temperature .
For some bacteria that live in extreme environments, the optimal temperature can be quite different than that, also the optimum pH. Sometimes there are subgroups within the same type of enzyme with different pH optimum (for example: acid phosphatases and alkaline phosphatases).
They are required in minimum concentrations
Given this specificity that characterizes them, only a very small amount of these proteins is necessary to carry out normal metabolic processes , as they function as a very efficient assembly line, which in a matter of seconds transforms a compound or several into another.
Minimal changes may lead to inactivation.
It should be kept in mind that sometimes the change of a few amino acids can mean the reduction of the activity of an enzyme or even the total loss of its activity. Also, enzymes can be oxidized , for example, and under those conditions they might be unable to catalyze a reaction.
Some agents lead to their activation
Some compounds can bind to the enzyme, not in the active site, but in another position , and motivate a conformational change that results in its activation. These are called allosteric activators or effectors.
Types of enzymes
Enzymes are classified according to the general type of reaction they catalyze . Some very important groups are made up of hydrolytic enzymes (which catalyze hydrolysis), oxide-reductases (which catalyze redox reactions), oxygenases (which introduce oxygen into the molecule ), polymerases (which join units to a repetitive structure), the phosphatases (releasing phosphate groups of a molecule).
The ability of some enzymes to carry out a process is sometimes used on an industrial scale, with the necessary adjustments to change the scale.
For example, amylase is used in the bakery industry , which is the enzyme that degrades starch and converts it into simpler sugars; These simple sugars are then used by the yeasts involved in the manufacture of bread.
Proteases are also used to break the structure of gluten and allow a good kneading, to achieve a more plastic dough.
Some enzymes need the simultaneous presence of other non-protein substances to operate. These substances are usually metal ions ( copper , manganese, magnesium ) or organic substances, in the latter case they are also often referred to as coenzymes.