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Question: Which of the following compounds, when added to stored whole blood, BEST prevents clotting?
(attached image of the molecular structures, which were given in question)
A. Citrate
B. Glutamate
C. Succinate
D. gamma-carboxyglutamate
Here is the relevant excerpt from the passage:
"Gamma-carboxyglutamate is an excellent chelator of Ca2+ and, following injury, acts as an anchoring mechanism between calcium-dependent coagulation factors and the phospholipid membranes of platelets. The functional significance of this event is that it brings specific factors together that aid in the formation of a clot, thereby accelerating clot formation many fold."
Answer: A, Citrate.
Explanation given: Citrate is the best chelator of Ca2+. Calcium is an important cofactor in blood clotting. Ca has a +2 charge, and can be chelated by certain compounds with negative charges. The more carboxyl groups on a molecule, the better the chelator, and the better the molecule is at preventing clotting in stored blood.
What I don't understand is why the best chelator of Ca2+ would be considered the best anti-coagulant. The passage seems contradictory because it states that gamma-carboxyglutamate is a great chelator, but that accelerates clot formation. What am I missing?
(attached image of the molecular structures, which were given in question)
A. Citrate
B. Glutamate
C. Succinate
D. gamma-carboxyglutamate
Here is the relevant excerpt from the passage:
"Gamma-carboxyglutamate is an excellent chelator of Ca2+ and, following injury, acts as an anchoring mechanism between calcium-dependent coagulation factors and the phospholipid membranes of platelets. The functional significance of this event is that it brings specific factors together that aid in the formation of a clot, thereby accelerating clot formation many fold."
Answer: A, Citrate.
Explanation given: Citrate is the best chelator of Ca2+. Calcium is an important cofactor in blood clotting. Ca has a +2 charge, and can be chelated by certain compounds with negative charges. The more carboxyl groups on a molecule, the better the chelator, and the better the molecule is at preventing clotting in stored blood.
What I don't understand is why the best chelator of Ca2+ would be considered the best anti-coagulant. The passage seems contradictory because it states that gamma-carboxyglutamate is a great chelator, but that accelerates clot formation. What am I missing?
