Navigation Links
Hydrolysis


Hydrolysis is a chemical process in which a molecule is cleaved into two parts by the addition of a molecule of water. This is distinct from a hydration reaction, in which water molecules are added to a substance, but no cleavage occurs.

Types

Hydrolysis of an ester link

In a hydrolysis reaction that involves breaking an ester link, one hydrolysis product contains a hydroxyl functional group, while the other contains a carboxylic acid functional group.

The fragment of the parent molecule that was originally a carboxylate gains a hydrogen ion from the additional water molecule. The fragment that was originally an alkyl group collects the remaining hydroxyl group from the water molecule.

Thus the ester is effectively reversed to its component alcohol and carboxylic acid.

Hydrolysing peptide link of amino acids

In other hydrolysis reactions such as hydrolysing the peptide links of amino acids only one of the products, the carboxylic acid product, has a hydroxide group derived from the water. The amine product gains the remaining hydrogen ion.

Hydrolysis can be considered as the opposite of condensation, in which two fragments are joined for each water molecule produced. As hydrolysis is a reversible reaction, condensation and hydrolysis can take place at the same time the position of equilibrium determining the amount of each product.

Irreversibility of hydrolysis under physiological conditions

Under physiological conditions (i.e. in dilute aqueous solution), a hydrolytic cleavage reaction, where the concentration of a metabolic precursor is low (on the order of 10-3 to 10-6 molar), is essentially thermodynamically irreversible. To give an example:

A + H2O → X + Y

Assuming that x is the final concentration of products, and that C is the initial concentration of A, and W = [H2O] = 55.5 molar, then x can be calculated with the equation:

let Kd×W = k

then

For a value of C = 0.001 molar, and k = 1 molar, x/C > 0.999. Less than 0.1% of the original reactant would be present once the reaction is complete.

This theme of physiological irreversibility of hydrolysis is used consistently in metabolic pathways, since many biological processes are driven by the cleavage of anhydrous pyrophosphate bonds.

See also

Hydrolysis


'"/>


(Date:8/21/2014)... aimed at improving the food intake, health and quality ... is among three projects at the University of Waterloo ... Canadian Institutes of Health Research (CIHR). , Professor ... at Waterloo, and a Schlegel research chair in nutrition ... investigate why many Canadians living in long-term care homes ...
(Date:8/21/2014)... has implications for life in other extreme environments, both ... LSU Associate Professor of Biological Sciences Brent Christner and ... NSF, this week published a paper confirming that the ... meters (2600 feet) beneath the surface of the West ... more than 400 subglacial lakes and numerous rivers and ...
(Date:8/21/2014)... the water window? It consists of radiations in the ... by the water in biological tissues. New theoretical findings ... within the water window. These could be the basis ... of the biological samples or to be used in ... physical mechanism needed to efficiently generate the harmonic radiationswhich ...
Breaking Biology News(10 mins):Grants will fund landmark aging research at Waterloo 2800 meters beneath Antarctic ice sheet, subglacial lake holds viable microbial ecosystems 2800 meters beneath Antarctic ice sheet, subglacial lake holds viable microbial ecosystems 3800 meters beneath Antarctic ice sheet, subglacial lake holds viable microbial ecosystems 4Water window imaging opportunity 2
... similarities between Grenoble and Hollywood or between the researchers ... (IBS) and world-known filmmakers. However, scientists from these institutes ... movie. The actors are not celebrities but a protein ... this protein in action by freezing it at several ...
... that hopes to use a patient's own immune cells to ... a specialty procedure performed in only a handful of institutions, ... , Julian A. Kim, M.D., chief of surgical oncology at ... the National Institutes of Health for a five-year study that ...
... 12 surgeons and 21 surgical residents, video game skill ... a simulated surgery skills course, according to a report ... of the JAMA/Archives journals. , James C. Rosser Jr., ... colleagues asked 33 surgeons (21 residents and 12 attending ...
Cached Biology News:Freeze! Scientists film proteins at work by freezing them at different states 2
Other biology definitionOther Tags