The
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
phosphoketolase()
catalyzes
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...
the
chemical reaction
A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...
s
:D-xylulose 5-phosphate + phosphate
acetyl phosphate + D-glyceraldehyde 3-phosphate + H
2O ()
:D-fructose 6-phosphate + phosphate
acetyl phosphate + D-erythrose 4-phosphate + H
2O
EC 4.1.2.22
:D-sedoheptulose 7-phosphate + phosphate
acetyl phosphate + D-ribose 5-phosphate + H
2O
Phosphoketolase is considered a
promiscuous
Promiscuity is the practice of engaging in sexual activity frequently with different partners or being indiscriminate in the choice of sexual partners. The term can carry a moral judgment. A common example of behavior viewed as promiscuous by man ...
enzyme because it was demonstrated to use 3 different
sugar phosphates as substrates. In a recent genetic study, more than 150 putative phosphoketolase genes exhibiting varying
catalytic
Catalysis () is the increase in reaction rate, rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst ...
properties were found in 650 analyzed bacterial genomes.
This enzyme belongs to the family of
lyase
In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bonds by means other than hydrolysis (a substitution reaction) and oxidation
Redox ( , , reduction–oxidation or oxidatio ...
s, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. It participates in 3
metabolic pathways
In biochemistry, a metabolic pathway is a linked series of chemical reactions occurring within a cell. The reactants, products, and intermediates of an enzymatic reaction are known as metabolites, which are modified by a sequence of chemical ...
:
pentose phosphate pathway
The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt or HMP shunt) is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses (five-carbon sugars) as well as ribose 5-ph ...
,
methane metabolism, and
carbon fixation
Biological carbon fixation, or сarbon assimilation, is the Biological process, process by which living organisms convert Total inorganic carbon, inorganic carbon (particularly carbon dioxide, ) to Organic compound, organic compounds. These o ...
. It employs one
cofactor,
thiamin diphosphate. Phosphoketolase was previously used for
biotechnological
Biotechnology is a multidisciplinary field that involves the integration of natural sciences and engineering sciences in order to achieve the application of organisms and parts thereof for products and services. Specialists in the field are kn ...
purposes as it enables the construction of synthetic pathways that allow complete carbon conservation without the generation of
reducing power.
References
*
*
EC 4.1.2
Thiamine enzymes
Enzymes of unknown structure
{{4.1-enzyme-stub