Question: Which enzyme catalyzes the first step of glycolysis?
Answer:
- Hexokinase is an enzyme that catalyzes the first step of glycolysis.
- It is responsible for the phosphorylation of glucose, converting it into glucose-6-phosphate (G6P).
- It transfers a phosphate group from ATP to the sixth carbon of glucose, forming G6P.
- Hexokinase is present in most tissues and has a high affinity for glucose, allowing it to effectively phosphorylate glucose even at low concentrations.
| Enzyme | Hexokinase |
| Function | Catalyzes the phosphorylation of glucose to glucose-6-phosphate (G6P) in the first step of glycolysis |
| Reaction | Glucose + ATP → Glucose-6-phosphate + ADP |
| Role in Glycolysis | Hexokinase commits glucose to glycolysis by converting it into glucose-6-phosphate |
| Substrate Specificity | Hexokinase has a high affinity for glucose, effectively phosphorylating it even at low concentrations |
| Regulatory Properties | Hexokinase is subject to feedback inhibition by G6P, which helps regulate glucose metabolism |
| Allosteric Regulation | Hexokinase can be regulated allosterically by factors such as glucose-6-phosphate and ATP |
| Tissue-Specific Isoforms | Glucokinase is a hexokinase isoform predominantly found in the liver and pancreas |
| Km (Michaelis constant) | Hexokinase has a low Km for glucose, indicating high affinity for its substrate |
| ATP Consumption | Hexokinase requires the hydrolysis of ATP to ADP for the phosphorylation reaction |
| Clinical Significance | Mutations in hexokinase genes can lead to rare genetic disorders, such as hexokinase deficiency |
| Commercial Availability | Hexokinase enzymes are available commercially for research and laboratory use |
Important Questions about Enzymes
- Enzymes MCQs
- Inhibition in enzymes
- Which enzyme digests starch?
- Which enzyme digests protein?
- which enzyme is present in saliva?
- Which enzyme is not present in succus entericus?
- Which enzyme breaks down protein in the stomach?
- Which enzyme converts fibrinogen to fibrin?
- Which enzyme converts glucose into alcohol?
- Which enzyme digests fat?
- Which enzyme digests milk protein?
- Which enzyme is used in PCR?
- Which enzyme unzips the DNA double helix?
- Which liver enzyme increases with alcohol?
- Which enzyme cuts DNA?
- Which enzyme catalyzes the first step of glycolysis?
- Which enzyme binds DNA fragments together?
- Which enzyme transcribes DNA into RNA?
- which enzyme adds new nucleotides?
- Which enzyme digests cellulose?
- Which enzyme separates the two strands of DNA?
- Which enzyme converts carbohydrates into glucose?
- Which enzyme removes RNA primer?
- Which enzymes help in digestion?
- Which enzyme works best in acidic conditions?
- Which enzyme synthesizes tRNA?
- Which enzyme secreted by pancreas?
- Which enzyme converts maltose into glucose?
- Which vitamins work as coenzyme?