We are all know what is dough ripens – it will expand, burst gas bubbles, the dough escapes from the vessel. We watch the fermentation process – enzyme action!
Even when we cut the Apple, and then it gets dark – this action of enzyme polyphenoloxidases. It is catalyst or just accelerates the oxidation of complex organic substances – polyphenols, in the cells of the apple.
(polyphenols are complex chemical substances, that have a benzene rings connected to a hydroxyl group OH).
Another example, when the wound on the skin to moisten with hydrogen peroxide (H2O2), we can see that hydrogen peroxide boils – is very intense release of atomic oxygen:
2Н2О2→ 2Н2О+O2
The decomposition of hydrogen peroxide is because our blood contains enzyme catalase. It breaks down the hydrogen peroxide to water and oxygen. Enzyme catalaseis necessary for our body, it helps to decomposition of hydrogen peroxide formed cell respiration.
Indeed, enzymes is a very important and necessary substances. The different it kinds contained in the gastric juice: some enzymes break down large molecules of fats, others decomposit the remains of these molecules, and others – form the cells of our body, etc.
There are enzymes phosphatase in our body, with main function is hydrolysis and decomposition the molecules of ester phosphoric acid. These enzymes allow to digest our body energy food – carbohydrates!
All living organisms live on Earth due to enzyme catalysis. Today there are over 2000 different enzymes. The names of enzymes use the end "ASE", and the first part of the word is a substance that is exposed to the action of this enzyme. You can know about the time of its opening, from name of enzyme, so very long time discovered enzymes – do not have these rules in its names.
Properties of enzymes
Although enzymes can be called catalysts, but still, they are very different.
1. The majority of enzyme molecules save their catalytic properties at a temperature about 40 °C, but at 70 °C completely lose its. Catalysts operate at temperatures from 200 to 500 °С.
2. The acidity of the environment, in which there are most enzymes, is about pH 7.4 is a neutral environment. This is stored in our blood. When it change on 0.4 in the "+" or "-" it has a bed effect in our body and is a result of the malfunction of enzymes. Some enzymes, as pepsin, operates at a pH of about 2...3 that is provided with a gastric juice (hydrochloric acid).
3. Enzymes can speed up chemical reactions in billions of times (in 1015 times) and some reactions not exist without them. An example is that the enzyme alcohol dehydrogenase (1 molecule) can to process 720 molecules of ethyl alcohol for 1 sec. and turn it into acetic aldehyde at room temperature. If we take 1 molecule of copper catalyst, it can handle at the same time with just 1 molecule of alcohol at 200 °С.
4. It is important that unlike many of the catalysts the action of enzyme does not depend on any other enzymes! Enzymes can affect to the molecules of some compounds, but does not affect to their isomers (same molecule but have a different spatial layout relationships). It allows to distinguish between different molecules that have the same chemical formula (composition one).
Action of enzymes
In the 19th century were presented to society different preparations containing the enzyme. In it time scientists are interested an action of enzymes and why it manifests such unique properties in chemical reactions.
In the end of 19th of century a German scientist chemist Hermann Emil Fischer began to study an action of enzymes. He undestud that each substance has its own "key" that allows in the chemical reactions to get from substance only those reaction products that are required and to reduce to a minimum the appearance of by-products. But such a model of the enzyme did not explain the reason why the enzyme in the reaction process is converted to another substance. On this theory are a few clarifications. The first clarification is that the enzyme an able to adjust to the reaction and to the substance that reacts. Thus there is a weakening of the intramolecular bonds of the enzyme and leading to the appearance of the high reactivity of the enzyme. Another clarification is that the particle of a substance on the enzyme changes its surface properties, so and changes the flexible form of the protein molecule of the enzyme. The deformation of the molecule leads to the convergence of reacting with each other substances, and substances in the enzyme catalyze the reaction. In fact the shape of reagents and enzymes is changing, but their rapprochement and mutual deformation relative to each other allows to catalyze the reaction.