Glucose-6-phosphate

Structural formula
	α- anomer of D -glucose-6-phosphate
General
Surname	Glucose-6-phosphate
other names	Robinson Esters; G-6-P;
Molecular formula	C 6 H 13 O 9 P
External identifiers / databases
EC number	200-286-9
ECHA InfoCard	100,000,261
PubChem	439958
DrugBank	DB03581
Wikidata	Q74566546
properties
Molar mass	260.14 g mol −1
safety instructions
GHS labeling of hazardous substances danger
H and P phrases	H: 314
	P: 280-305 + 351 + 338-310
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Glucose-6-phosphate (synonyms: Robinson ester; G-6-P) is an organic molecule that plays an important role in the metabolism of almost all living things. It consists of a glucose molecule (grape sugar) with a phosphate residue attached to its sixth carbon atom. The normal content of glucose-6-phosphate in the erythrocytes is 39–127 μmol / l.

meaning

Glucose-6-phosphate is an important metabolite in cell metabolism . During glycolysis it is produced from glucose with the consumption of ATP .

The hexokinase reaction

{\ displaystyle \ mathrm {Glucose + ATP + H_ {2} O {\ text {}} {\ xrightarrow {Hexokinase}} {\ text {}} G {\ text {-}} 6 {\ text {-}} P + ADP + H_ {3} O ^ {+}}}

is catalyzed by the enzymes hexokinase I-IV. The reaction is exergonic and irreversible under standard conditions with ΔG ⁰ '= −13.7 kJ / mol. Under physiological conditions, for example in the course of glycolysis , ΔG = −33.9 kJ / mol.

Through this reaction, glucose is “activated”, ie converted into a more energetic molecule. The amount of energy used is released again in subsequent reaction steps.

In the next step of glycolysis, glucose -6-phosphate is isomerized to fructose-6-phosphate . The enzyme that catalyzes this reaction is glucose-6-phosphate isomerase . Glucose-6-phosphate isomerase can be inhibited by the analogue 2-deoxy- D -glucose .

More reactions

1. Glucose-6-phosphate can be oxidized to 6-phosphogluconolactone by the enzyme glucose-6-phosphate dehydrogenase during the pentose phosphate cycle . This creates the NADPH required for fatty acid and steroid biosynthesis. The metabolic disease glucose-6-phosphate dehydrogenase deficiency is particularly widespread in Central Africa.

2. In the course of glycogen synthesis , glucose-6-phosphate can be converted to glucose-1-phosphate. This reaction is catalyzed by the enzyme glucose-6-phosphate mutase. The glucose-1-phosphate can then be linked to "animal starch" ( glycogen ), which happens in humans in the liver.

3. In gluconeogenesis , glucose-6-phosphate is produced from fructose-6-phosphate by the phosphohexose isomerase reaction. In skeletal muscle , glucose-6-phosphate is the end product of glycogenolysis . In the endoplasmic reticulum of the liver and kidneys , glucose-6-phosphate can be broken down into glucose by the enzyme glucose-6-phosphatase . A defect in glucose-6-phosphatase leads to von Gierke disease type Ia.

Individual evidence

↑ ^a ^b Data sheet D-Glucose 6-phosphate solution from Sigma-Aldrich , accessed on April 3, 2011 ( PDF ).
^ Reginald Garrett and Charles M. Grisham: Biochemistry . (International Student Edition). Cengage learning services; 4th edition 2009; ISBN 978-0-495-11464-2 ; P. 538

[Sigma-1] Data sheet D-Glucose 6-phosphate solution from Sigma-Aldrich , accessed on April 3, 2011 ( PDF ).

[2] Reginald Garrett and Charles M. Grisham: Biochemistry . (International Student Edition). Cengage learning services; 4th edition 2009; ISBN 978-0-495-11464-2 ; P. 538