# hydrolysis

The hydrolysis ( ancient Greek ὕδωρ hydor "water" and λύσις lýsis "solution, dissolution, termination") is the splitting of a (bio) chemical compound through reaction with water . In the process, a hydrogen atom is (formally) transferred to one “split piece”, the remaining hydroxy residue is bound to the other split piece. The reverse of the hydrolysis is a condensation reaction . If the solvent is also water in the reaction, hydrolysis is a solvolysis .

In general:

${\ displaystyle \ mathrm {{\ color {Red} X {-} Y} \ + \ {\ color {Blue} H {-} OH} \ longrightarrow \ {\ color {Red} X {-}} {\ color {Blue} H} \ + \ {\ color {Red} Y} {\ color {Blue} {-} OH}}}$
Hydrolysis of compound XY.

Deviating from the above definition, the term hydrolysis , also known as salt hydrolysis , was used by Arrhenius to describe basic or acidic reactions that occur when salts are dissolved, the acid or base residues of which are derived from weak acids or weak bases. The hydrolysis here is a reversal of the neutralization . See Arrhenius' acid-base concept .

## Examples

Most of the hydrolyses listed above run better and faster if the reaction is carried out in an acidic or basic medium instead of at neutral pH. Examples are the acid hydrolysis of esters , which is the reverse reaction to the esterification , and the saponification taking place in the base .

## Enantioselective hydrolysis

Esters of chiral carboxylic acids or chiral alcohols can be hydrolyzed enantioselectively under the influence of lipases . Enantiomerically pure alcohols or enantiomerically pure carboxylic acids are formed. Similarly, racemic amides can be hydrolyzed enantioselectively in the presence of acylases . The process is used industrially for the production of the amino acid L- methionine from N -acetyl- DL- methionine.

## Hydrolysis of biomolecules

Through hydrolysis, many biomolecules (e.g. proteins , disaccharides , polysaccharides or fats ) are broken down into their building blocks ( monomers ) in the metabolism , usually under catalysis by an enzyme ( hydrolase ).

An important hydrolysis reaction that gives proteins energy for mechanical work, transport processes, etc. there is the cleavage of ATP to ADP and a phosphate residue .

When analyzing the amino acid composition of proteins, purified proteins are hydrolyzed by high concentrations of hydrochloric acid in the absence of air and at temperatures> 100 ° C. By means of the hydrolyzate of the protein - with knowledge of the respective stability of the released amino acids under standard conditions and their correction factors - conclusions can be drawn about the proportion of the peptide-bound amino acid in the structure of the protein.

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