The
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
phosphoketolase()
catalyzes the
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
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 Sexual partner, partners or being indiscriminate in the choice of sexual partners. The term can carry a moral judgment. A common example of behavior viewed as pro ...
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 process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
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, often forming a new double bond or a new ring structure. ...
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 reac ...
:
pentose phosphate pathway
The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt and the HMP Shunt) is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-pho ...
,
methane metabolism, and
carbon fixation
Biological carbon fixation or сarbon assimilation is the process by which inorganic carbon (particularly in the form of carbon dioxide) is converted to organic compounds by living organisms. The compounds are then used to store energy and as ...
. It employs one
cofactor,
thiamin diphosphate
Thiamine pyrophosphate (TPP or ThPP), or thiamine diphosphate (ThDP), or cocarboxylase is a thiamine (vitamin B1) derivative which is produced by the enzyme thiamine diphosphokinase. Thiamine pyrophosphate is a cofactor that is present in all liv ...
. Phosphoketolase was previously used for
biotechnological
Biotechnology is the integration of natural sciences and engineering sciences in order to achieve the application of organisms, cells, parts thereof and molecular analogues for products and services. The term ''biotechnology'' was first used by ...
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