Question:
Which of the following clotting factors in a patient on warfarin therapy would have decreased gamma-carboxyglutamate residues?
Which of the following clotting factors in a patient on warfarin therapy would have decreased gamma-carboxyglutamate residues?
Show Hint
Only the 2, 7, 9, 10 (and proteins C, S, Z) group is undercarboxylated by warfarin.
Updated On: Jun 23, 2026
- Factor 2
- Factor 11
- Tissue factor
- Factor 5
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: Recall warfarin's mechanism. Warfarin blocks vitamin K epoxide reductase, lowering reduced vitamin K. Vitamin K is the cofactor for gamma-glutamyl carboxylase, the enzyme that adds gamma-carboxyglutamate (Gla) residues to certain clotting factors. These Gla residues let the factors bind calcium and phospholipid surfaces.
Step 2: List the vitamin K-dependent factors. They are factors 2, 7, 9, and 10, plus proteins C, S, and Z. On warfarin, these factors are made but undercarboxylated, so they have fewer functional gamma-carboxyglutamate residues.
Step 3: Match the options. Only Factor 2 (prothrombin) in the list is vitamin K-dependent, so option (a) is correct. Factor 11 and Factor 5 are not vitamin K-dependent, and tissue factor is a cell-surface protein, not a vitamin K-dependent Gla protein.
Ref: Standard biochemistry of vitamin K-dependent carboxylation.
Step 2: List the vitamin K-dependent factors. They are factors 2, 7, 9, and 10, plus proteins C, S, and Z. On warfarin, these factors are made but undercarboxylated, so they have fewer functional gamma-carboxyglutamate residues.
Step 3: Match the options. Only Factor 2 (prothrombin) in the list is vitamin K-dependent, so option (a) is correct. Factor 11 and Factor 5 are not vitamin K-dependent, and tissue factor is a cell-surface protein, not a vitamin K-dependent Gla protein.
Ref: Standard biochemistry of vitamin K-dependent carboxylation.
Was this answer helpful?
0
0
Top NEET PG Biochemistry Questions
- Which of the following clotting factors is needed for gamma-glutamyl carboxylase?
- A patient presented with diarrhea, dermatitis, and dementia. Which of the following vitamin deficiencies would you suspect in this patient?
- A young boy presents to the OPD with hypoglycemia and muscle cramps, on exertion or while playing. Then he becomes normal after resting for a while. These episodes are recurrent after a period of activity. He has decreased serum lactate and glucose levels. Which of the following diseases is he most likely to be suffering from?
- A family consumes only polished rice. Which of the following combinations of vitamin deficiency and enzymatic defect will be present in this family?
- A chronic alcoholic patient presented to the casualty with confusion, ataxia, and painful eye movements. What could be the vitamin deficiency seen in this patient?
View More Questions
Top NEET PG Vitamin K and clotting factors Questions
Top NEET PG Questions
- A patient hailing from Delhi presents with fever, arthralgia, and extensive petechial rash for 3 days. Lab investigations revealed a hemoglobin of 9 g/ dL, a white blood cell count of 9000 cells/mm3, a platelet count of 20000 cells/mm3, and a prolonged bleeding time. The clotting time was normal. What is the most likely diagnosis?
- Which of the following statements is true about Trichomonas vaginalis?
- A lady from West Rajasthan presented with an ulcer surrounded by erythema on the right leg. Microscopy of the biopsy from the edge of the ulcer showed organisms with dark staining nuclei and kinetoplast. What is the most likely causative agent?
- A child presents with a fever and a rash. Urine examination showed cells with owl's eye appearance. What is the most likely diagnosis?
- Infection with Clonorchis sinensis is associated with an increased risk of__?
View More Questions