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This passage is the one I had most trouble with and need help. I feel really stupid for not understanding this even with online sources and looking at the answer keys.
Questions 9: Glutamate is converted to gamma-carboxyglutamate in the vitamin K dependent reaction shown below. The enzyme which BEST regenerates vitamin K hydroquinone is called a:
a)decarboxylase
b)carboxylase
c)reductase
d)protease
initially, I chose a because glutamate is carboxylated to form gamma carboxyglutamate. Therefore I reasoned that in order to turn back, it needs to be decarboxylated. I used the same reasoning for Hydroquinone to quionone and reverse reaction.
Question 13. which of the following compounds when added to store whole blood, BEST prevents clotting?
a)citrate
b)glutamate
c)succinate
d)gamma-carboxyglutamate
Initially, I chose citrate after ruling out B and C. As the passage suggested, they are needed to blood clotting and it goes against what the question is asking. Then I was down to citrate and succinate. The only difference is the number of COO- bonds and I randomly chose citrate. The answer key says + charge on glutamate and gamma-carboxyglutamate will repel the Ca2+ and Ca are chelators which will act as anchoring mechanism. However wouldn't three - charge on citrate attract citrate more strongly and form clotting?
Let me know if anything doesn't make sense.
Questions 9: Glutamate is converted to gamma-carboxyglutamate in the vitamin K dependent reaction shown below. The enzyme which BEST regenerates vitamin K hydroquinone is called a:
a)decarboxylase
b)carboxylase
c)reductase
d)protease
initially, I chose a because glutamate is carboxylated to form gamma carboxyglutamate. Therefore I reasoned that in order to turn back, it needs to be decarboxylated. I used the same reasoning for Hydroquinone to quionone and reverse reaction.
Question 13. which of the following compounds when added to store whole blood, BEST prevents clotting?
a)citrate
b)glutamate
c)succinate
d)gamma-carboxyglutamate
Initially, I chose citrate after ruling out B and C. As the passage suggested, they are needed to blood clotting and it goes against what the question is asking. Then I was down to citrate and succinate. The only difference is the number of COO- bonds and I randomly chose citrate. The answer key says + charge on glutamate and gamma-carboxyglutamate will repel the Ca2+ and Ca are chelators which will act as anchoring mechanism. However wouldn't three - charge on citrate attract citrate more strongly and form clotting?
Let me know if anything doesn't make sense.
