Glucose 1,6 bisphosphate

Structural formula
α- anomer of D -glucose-1,6-bisphosphate ( pyranose form )
General
Surname	Glucose 1,6 bisphosphate
other names	G16bP Glucose-1,6-diphosphate (obsolete)
Molecular formula	C 6 H 14 O 12 P 2
External identifiers / databases
CAS number 305-58-8 PubChem 82400 ChemSpider 8580400 DrugBank DB02835 Wikidata Q4122197
properties
Molar mass	340.12 g mol −1
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Glucose-1,6-bisphosphate is a diester of glucose and two molecules of phosphoric acid . It is an intermediate in carbohydrate metabolism . Physiologically, only the D isomer plays a role.

Occurrence

D- glucose-1,6-bisphosphate was found particularly in the erythrocytes , brain and skeletal muscles . It was first discovered in yeast extract in 1948 .

meaning

Various functions are known and described in the literature for glucose-1,6-bisphosphate:

• Under experimental conditions, an inhibitory effect on hexokinase was observed in erythrocytes . The enzyme catalyzes the initial reaction in glycolysis . In addition, an inhibiting effect on fructose-1,6-bisphosphatase and 6-phosphogluconate dehydrogenase was demonstrated.

• G16bP can activate phosphofructokinase 1 and pyruvate kinase .

• It acts as a cofactor for the enzyme phosphoglucomutase (see below). A similar reaction also occurs with phosphopentomutase ( EC  5.4.2.7 ), which leads to the formation of ribose-5-phosphate / ribose-1-phosphate .

Reactions

Rearrangement of α-D-glucose-1-phosphate (G1P) to α-D-glucose-6-phosphate (G6P), catalyzed by phosphoglucomutase (PGM). In this reaction, a phosphate group is transferred to the enzyme-bound α-D-glucose-1,6-bisphosphate (G16bP) .

Glucose-1,6-bisphosphate is the essential intermediate in the mutual rearrangement of α- D - glucose-1-phosphate to α- D - glucose-6-phosphate . The reactions are part of glycogen and starch breakdown , glycogen synthesis , uronic acid metabolism and galactose metabolism.

The rearrangement is catalyzed by phosphoglucomutase (PGM). A phosphate group of the enzyme-bound molecule α- D -glucose-1,6-bisphosphate is transferred. Since the reaction also produces G16bP as a regenerated cofactor, this does not appear in the gross reaction equation:

${\displaystyle \mathrm {\alpha {\text{-D-Glc-1P}}\rightleftharpoons \ \alpha {\text{-D-Glc-6P}}} }$

Alternatively, α- D -G16bP is formed together with D - 3-phosphoglycerate (3PG) from D - 1,3-bisphosphoglycerate (1,3BPG) and α- D- glucose-1-phosphate, which is the glucose-1,6-bisphosphate -Synthase catalyzed ( EC  2.7.1.106 ):

${\displaystyle \mathrm {{\text{1,3BPG}}+G1P\longrightarrow 3PG+G16bP} }$

The representation of G16bP by the enzyme glucose-1-phosphate phosphodismutase ( EC  2.7.1.41 ) is also known. This catalyzes the conversion of two molecules of glucose-1-phosphate according to:

${\displaystyle \mathrm {2\ {\text{Glucose-1-phosphat}}\rightleftharpoons \ G16bP+Glucose} }$

Finally, G16bP is formed by transferring a phosphate group to glucose-1-phosphate, which is done by means of a glucose-1-phosphate kinase ( EC  2.7.1.10 ) while consuming ATP :

${\displaystyle \mathrm {{\text{Glucose-1-phosphat}}+ATP\longrightarrow \ G16bP+ADP} }$

literature

• Carreras, J. et al. (1986): Bisphosphorylated metabolites of glycerate, glucose, and fructose: functions, metabolism and molecular pathology . In: Clin Biochem. 19 (6); 348-358; PMID 3555887 ; doi : 10.1016 / S0009-9120 (86) 80008-X

Individual evidence

1. ↑ Data sheet α-D-Glucose 1,6-bisphosphate potassium salt hydrate from Sigma-Aldrich , accessed on May 22, 2017 ( PDF ).
2. ↑ E. Piatti et al. : Glucose 1,6-bisphosphate-overloaded erythrocytes: a strategy to investigate the metabolic role of the bisphosphate in red blood cells. In: Arch Biochem Biophys . 293, No. 1, 1992, pp. 117-121, doi : 10.1016 / 0003-9861 (92) 90373-5 , PMID 1309980 .
3. ^ AM Bassols, J. Carreras, R. Cussó: Changes in glucose 1,6-bisphosphate content in rat skeletal muscle during contraction. In: Biochem J . 240, No. 3, 1986, pp. 747-751, PMID 3827864 .
4. ↑ V. Yip, ME Pusateri, J. Carter, IA Rose, OH Lowry: Distribution of the glucose-1,6-bisphosphate system in brain and retina . In: J Neurochem . 50, No. 2, February 1988, pp. 594-602. doi : 10.1111 / j.1471-4159.1988.tb02952.x . PMID 2826701 .
5. ^ HO Kammen, R. Koo: Phosphopentomutases. I. Identification of two activities in rabbit tissues . In: J Biol Chem . 244, No. 18, September 1969, pp. 4888-4893. PMID 5824563 .
6. ↑ Glucose-1,6-diphosphate. In: Compact lexicon of biology at Spektrum.de . Retrieved September 28, 2014 .