What is the definition of hydrophobic force?

The hydrophobic interaction force, referred to as the hydrophobic force, is not a discussion of the interaction force between molecules, but mainly a discussion of the adsorption force, which is a discussion of the effect of solvents on solutes. To be precise, it is the force exerted by solvent molecules on solute molecules, which is the same as that of molecular equilibrium in the separation process, which is a microscopic process, but the change of this microscopic process will cause a change in macroscopic thermodynamic quantities.

Biochemical processes include conformational changes of biological macromolecules, protein folding, binding of enzymes to substrates, enzymes combining several branched chains to form multi-branched enzymes, and biofilms formed by the high degree of condensation of biological macromolecules, and the occurrence of these processes is mainly driven by hydrophobic interaction forces.

The hydrophobic interaction is a force that is related to, but not identical, to van der Waals forces.

Hydrophobic forces. The hydrophobic force is also known as the hydrophobic bond. It is made up of hydrophobic groups of side chains approaching each other. and form a force. for the maintenance of molecules.

Significance:Pressurized waterWater is released under the compression of the rock and expansion of the water, while the submersible chamber releases water under the action of gravity

Difference: Gravity release is due to gravity, whereas elastic release is due to the effect of lower water head, decompression along with gravity.

The elastic water release coefficient (elastic water supply) refers to the amount of water released by the confined aquifer per unit area when the pressure drops by one unit, also known as the water supply degree of elastic Wu Zhaoming.

Hydrophobic interactions are the main drivers of protein folding. The phenomenon of hydrophobic groups aggregating in close proximity to each other to avoid water is called hydrophobic interaction. Proteins are stable in water when the hydrophobic side chains in the protein aggregate inside the protein instead of being solvated by water.

Hydrophobic interactions play a major role in maintaining protein conformation, as water molecules interact more strongly with each other than with other nonpolar molecules. Non-polar side chains aggregate inside protein molecules to avoid water. At the same time, most polar side chains maintain contact with water on the surface of the protein.

The hydrophobic properties inside the molecule explain not only the aggregation of hydrophobic residues, but also the stability of helices and folded sheets.

The hydrophobic reciprocal interaction occurs through the mutual repulsion of the hydrophobic group of hydrophobic substances and the water, and the hydrophobic group is generally a non-polar group. This action brings the hydrophobic groups closer to each other, while at the same time concentrating and structuring the water to a greater extent.

Cage hydrate: A dry ice-like inclusion formed by hydrophobic interactions, where the "host" substance, i.e., water, forms a cage-like structure through hydrogen bonding, physically retaining a "guest" substance, i.e., small hydrophobic molecules. Caged hydrates represent the largest structural response of water to a non-polar substance, and similar microstructures are naturally present in biological matter.

Hydrophobic interactions are critical to the structure and properties of most proteins. The hydrophobic interaction provides the main impetus for the folding of proteins, allowing the hydrophobic residues to be located inside the protein molecule. Interestingly, although most of the hydrophobic groups of the protein aggregate each other due to hydrophobic interactions, about 1 3 of the hydrophobic groups are still exposed to the water, so the special structure of the water on the hydrophobic surface is present in the hydration structure of the protein.

Lowering the temperature makes the hydrophobic interaction weaker and the hydrogen bond stronger.

The length of hydrophobic interactions can reach about 100 nanometers, but the molecular forces of hydrophobic interactions are only about 5 nanometers at most. However, the study of such a long range of hydrophobic interactions has not yet reached satisfactory conclusions.

Hydrophobic force refers to the force by which the folding of globular proteins in an aqueous medium always tends to bury hydrophobic residues inside the molecule.

The essence of hydrophobic action is entropy, and the equilibrium state of an isolated system is the product of the best compromise between entropy and energy. Hydrophobic interactions play a major role in maintaining protein conformation, as water molecules interact more strongly with each other than with other nonpolar molecules.

The hydrophobic interaction force, referred to as the hydrophobic force, is not a discussion of the interaction force between molecules, but mainly a discussion of the adsorption force, which is a discussion of the effect of solvents on solutes. To be precise, it is the force exerted by solvent molecules on solute molecules, which is the same as that of molecular equilibrium in the separation process, which is a microscopic process, but the change of this microscopic process will cause a change in macroscopic thermodynamic quantities.

Biochemical processes include the conformational changes of biological macromolecules, protein folding, the binding of enzymes and substrates, the combination of several branched chains to form multi-branched enzymes, and the biofilm formed by the high condensation of biomass macromolecules.

The hydrophobic interaction is a force that is closely related to, but not identical, to van der Waals forces.

When there are non-polar groups (e.g., hydrocarbon groups) in a molecule, there is a mutual repulsion between a water molecule (and any polar molecule or polar group in a molecule in a broad sense), and this repulsion is called hydrophobic.

However, in terms of strictly physical nature, this definition is not very accurate and can be considered a popular understanding. In fact, the intermolecular or intermolecular forces usually manifest themselves as gravitational forces, and the repulsive force will only manifest itself when the intermolecular distance is extremely small due to strong compression. Therefore, the interaction between molecules or groups is usually gravitational and not truly mutually exclusive.

It's just that the gravitational pull between molecules or groups with similar polarities is stronger (between polar and polar or between non-polar and non-polar), while the gravitational pull between polar and non-polar is less. As a result, non-polar groups tend to be close to each other and move away from polar groups (not that there is a real repulsion between them).

I'll give you an example: the phospholipid bilayer.

As you know, the phospholipid bilayer is composed of a hydrophilic head and a hydrophobic tail, which is related to his constituent substance. Its head is mainly composed of phosphoric acid, and its tail is mainly composed of fatty acids.

1. The phosphate group is a hydrophilic group, and the common hydrophilic groups include sulfonic acid group, carboxyl group, hydroxyl group, etc. Because these groups increase the solubility of the substance. For example:

When a sulfonic acid group is introduced into the benzene ring to form benzene sulfonic acid, the water-insoluble nature of benzene becomes water-soluble benzene sulfonic acid. Therefore, the sulfonic acid group is a hydrophilic group, and the phosphate group is also a hydrophilic group.

2.On the contrary, all hydrocarbon groups are hydrophobic groups, that is, lipophilic (oil) groups, and as the carbon number of the hydrocarbon is larger (the longer the hydrocarbon chain) the hydrophobicity becomes, the lipophilic is stronger, and the less soluble it is in water.

As more and more protein crystal structures are resolved, the general rules of protein stereostructure are becoming clearer.

In the case of a globular protein, their surface is often surrounded by a layer of hydrophilic residues, and residues with hydrophobic side chains are in principle inside the molecule, but not absolutely. Strictly speaking, the hydrophobic residues of the whole protein molecule are gradually decreasing from the inside out, while the hydrophilic residues are increasing. Comparatively, hydrophilic residues are more likely to appear inside the molecule than hydrophobic residues are present on the surface of the molecule.

Because many charged residues form salt bonds through the interaction of positive and negative charges, or the side chains of some residues are involved in the formation of hydrogen bonds, the hydrophilicity of the residues is weakened, and the hydrophobic properties of some side chains are more prominent. Another example is the carbonyl and imide groups within the peptide bond in the peptide chain backbone, both of which are hydrophilic and form hydrogen bonds. There are also some hydrophobic residues on the surface of globular proteins, which are in an unstable state from an energetic point of view, and they tend to become more stable.

The side chains of these residues often become active sites of proteins and participate in interactions with other molecules. It is either involved in the interaction between subunits and subunits to form the quaternary structure of proteins, or it is associated with itself or with other molecules. In the case of membrane proteins, the peptides that cross the membrane in their peptide chains often form amphiphilic helices or folds. They have a large number of hydrophobic residues concentrated on one side and many hydrophilic residues on the other side.

Some membrane proteins have multiple peptides that cross the membrane, and the hydrophobic hydrophobic surface of the amphiphilic helix formed by these peptides faces the aliphatic chain in the membrane lipid, and the hydrophilic surface is facing away from the aliphatic chain, and is also arranged in a specific way to avoid contact with the hydrophobic environment as much as possible, and at the same time cooperate with each other to form a certain hydrophilic microenvironment. Some proteins that cross the membrane at one time also tend to have a tendency to form dimerization or multimerization, and the result is that the peptides that cross the membrane are more energetically stable.

In summary, protein structure is characterized by hydrophobic and hydrophilic equilibrium, and the stability of its structure depends largely on intramolecular hydrophobicity. Of course, it is not only hydrophobic interaction that stabilizes the structure of proteins, but also hydrogen bonds, salt bonds, and van der Waals forces, as well as disulfide bonds within the peptide chain, and coordination bonds between the peptide chain and the metal elements contained therein. However, from the perspective of the contribution of various factors, hydrophobic interaction is the most important.