hexokinase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: ATP + D-hexose = ADP + D-hexose 6-phosphate. [EC:2.7.1.1]
Hexokinase activity is a crucial step in glucose metabolism, catalyzing the phosphorylation of glucose to glucose-6-phosphate. This reaction is essential for several reasons:
1. **Trapping Glucose:** Glucose-6-phosphate is charged and unable to readily cross cell membranes, effectively trapping glucose within the cell. This maintains a concentration gradient for glucose uptake, ensuring continuous supply.
2. **Metabolic Commitment:** Phosphorylation of glucose commits it to further metabolism, preventing its diffusion out of the cell and directing it towards glycolysis or other metabolic pathways.
3. **Regulation of Glucose Metabolism:** Hexokinase activity is tightly regulated, influenced by factors like glucose concentration, ATP levels, and product inhibition. This regulation ensures that glucose metabolism is responsive to the cell's energy needs.
4. **First Step in Glycolysis:** Glucose-6-phosphate is the first intermediate in glycolysis, the central pathway for glucose catabolism. This pathway yields ATP, the primary energy currency of the cell, and provides precursors for other essential metabolic processes.
The mechanism of hexokinase activity involves the following steps:
1. **Binding of Glucose:** Glucose binds to the active site of the enzyme.
2. **Phosphorylation:** The enzyme uses ATP to transfer a phosphate group to glucose, forming glucose-6-phosphate.
3. **Release of Products:** Glucose-6-phosphate and ADP are released from the enzyme.
Hexokinase activity is essential for all organisms that utilize glucose as a primary energy source. It plays a critical role in energy production, metabolic regulation, and cellular homeostasis.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Hexokinase-2 | A hexokinase-2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P52789] | Homo sapiens (human) |
Compounds (2)
| 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 |
| andrographolide | carbobicyclic compound; gamma-lactone; labdane diterpenoid; primary alcohol; secondary alcohol | anti-HIV agent; anti-inflammatory drug; antineoplastic agent; metabolite |