Pyruvate kinase deficiency causes chronic haemolytic anaemia in adults. The biochemical basis for haemolysis in this enzyme deficiency is primarily:

• A Impaired HMP shunt leading to oxidative stress
• B Accumulation of 2,3-bisphosphoglycerate reducing oxygen delivery
• C Heinz body formation from denatured hemoglobin
• D ATP depletion impairing Na+/K+-ATPase pump and membrane integrity ✓

Explanation

Pyruvate kinase catalyses the final ATP-generating step in glycolysis (phosphoenolpyruvate → pyruvate + ATP). Red blood cells depend entirely on anaerobic glycolysis for ATP; loss of PK activity depletes ATP. This impairs the Na+/K+-ATPase pump, causing cation imbalance, osmotic swelling, rigid membrane, and ultimately haemolysis via extravascular destruction in the spleen. Paradoxically, 2,3-BPG accumulates upstream, which actually improves tissue oxygen delivery (right-shifted ODC) and partly explains why clinical anaemia is better tolerated than expected (haemolytic anaemia with compensatory polycythaemia).

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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