glucokinase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: ATP + D-glucose = ADP + D-glucose-6-phosphate. [EC:2.7.1.2]
Glucokinase activity is a critical enzyme involved in the first committed step of glucose metabolism. It catalyzes the phosphorylation of glucose to glucose-6-phosphate (G6P), utilizing ATP as a phosphate donor. This reaction is essential for glucose entry into glycolysis, the primary pathway for glucose breakdown to generate energy.
Glucokinase exhibits distinct kinetic properties compared to other hexokinases, displaying a lower affinity for glucose but a higher capacity for glucose phosphorylation at high glucose concentrations. This allows glucokinase to function as a glucose sensor in the liver and pancreatic β-cells, playing a vital role in regulating insulin secretion and hepatic glucose homeostasis.
Specifically, in pancreatic β-cells, glucokinase activity is crucial for glucose-stimulated insulin secretion (GSIS). As blood glucose levels rise, increased glucose uptake by β-cells leads to elevated glucokinase activity. The resulting increase in G6P levels stimulates a signaling cascade that ultimately leads to insulin release. This mechanism ensures that insulin secretion is tightly regulated by blood glucose levels, preventing hyperglycemia.
In the liver, glucokinase plays a significant role in regulating hepatic glucose production and storage. When blood glucose levels are high, glucokinase activity promotes glucose uptake and conversion to glycogen, the storage form of glucose. Conversely, when blood glucose levels are low, glucokinase activity is reduced, allowing the liver to release glucose into the bloodstream to maintain blood glucose homeostasis.
Furthermore, glucokinase exhibits tissue-specific expression patterns. While it is highly expressed in the liver and pancreatic β-cells, its expression is much lower in other tissues. This selective expression further emphasizes its critical role in regulating glucose metabolism in these specific organs.
In summary, glucokinase activity is an essential enzyme that plays a crucial role in glucose metabolism by catalyzing the phosphorylation of glucose to G6P. Its unique kinetic properties and tissue-specific expression patterns make it a key regulator of glucose homeostasis, insulin secretion, and hepatic glucose production and storage.'
"
Proteins (4)
| Protein | Definition | Taxonomy |
|---|---|---|
| Hexokinase-2 | A hexokinase-2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P52789] | Homo sapiens (human) |
| Hexokinase-4 | A hexokinase-4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P35557] | Homo sapiens (human) |
| Hexokinase-2 | A hexokinase-2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P52789] | Homo sapiens (human) |
| Hexokinase-4 | A hexokinase-4 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P35557] | Homo sapiens (human) |
Compounds (9)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| benserazide | benserazide : A carbohydrazide that results from the formal condensation of the carboxy group of DL-serine with the primary amino group of 4-(hydrazinylmethyl)benzene-1,2,3-triol. An aromatic-L-amino-acid decarboxylase inhibitor (DOPA decarboxylase inhibitor) that does not enter the central nervous system, it is used as its hydrochloride salt as an adjunct to levodopa in the treatment of parkinsonism. By preventing the conversion of levodopa to dopamine in the periphery, it causes an increase in the amount of levodopa reaching the central nervous system and so reduces the required dose. Benserazide has no antiparkinson actions when given alone. Benserazide: An inhibitor of DOPA DECARBOXYLASE that does not enter the central nervous system. It is often given with LEVODOPA in the treatment of parkinsonism to prevent the conversion of levodopa to dopamine in the periphery, thereby increasing the amount that reaches the central nervous system and reducing the required dose. It has no antiparkinson actions when given alone. | carbohydrazide; catechols; primary alcohol; primary amino compound | antiparkinson drug; dopaminergic agent; EC 4.1.1.28 (aromatic-L-amino-acid decarboxylase) inhibitor |
| staurosporine | indolocarbazole alkaloid; organic heterooctacyclic compound | apoptosis inducer; bacterial metabolite; EC 2.7.11.13 (protein kinase C) inhibitor; geroprotector | |
| zm 241385 | ZM 241385: a high affinity radioligand selective for the A2a adenosine receptor | diamino-1,3,5-triazine | |
| andrographolide | carbobicyclic compound; gamma-lactone; labdane diterpenoid; primary alcohol; secondary alcohol | anti-HIV agent; anti-inflammatory drug; antineoplastic agent; metabolite | |
| ro-28-1675 | acetamides | ||
| piragliatin | piragliatin: glucokinase activator | ||
| pf-04991532 | |||
| pf-04937319 | N,N-dimethyl-5-((2-methyl-6-((5-methylpyrazin-2-yl)carbamoyl)benzofuran-4-yl)oxy)pyrimidine-2-carboxamide: a glucokinase activator; structure in first source | ||
| agi-5198 | AGI-5198: inhibits isocitrate dehydrogenase 1; structure in first source |