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  #1  
Old 03-24-2012
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Biochemistry An enzyme in the cytosol

A SAMPLE OF LIVER PARENCHYMA IS HOMOGENIZED AND CENTRIFUGED TO REMOVE MEMBRANE COMPONENTS AND ORGANELLES LEAVING ONLY THE CYTOSOL AND THE PROTEINS IT CONTAINS. WHICH OF THE FOLLOWING ENZYME ACTIVITIES IS MOST LIKELY PRESENT IN THE HOMOGENATE?
A. Pyruvate Carboxylase
B. Ornithine Transcarbamoylase
C. Transketolase
D. Succinate Dehydrogenase
E. 3-Hydroxy-3-methylglutaryl-CoA lyase
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  #2  
Old 03-24-2012
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B. Ornithine transcarbamoylase?
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  #3  
Old 03-24-2012
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Its A Uworld Question! and the answer is transketolase. the only enzyme tht is in the cytoplasm among the list. the rest are present within the mitochondria.
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Old 03-24-2012
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Yes!! it is C. TRANSKETOLASE.
"Biochemical processes for cellular metabolism occur in distinct locations within cells. For example, beta oxidation of fatty acids, ketogenesis, the citric acid cycle, parts of the urea cycle (carbamoyl phophate) synthetase1 and ornithine transcarbamoylase) and pyruvate carboxylation all occur exclusively within the mitochondria.
TRANSKETOLASE is an enzyme of the pentose phosphate pathway that uses thiamine (vit. B1) as a cofactor. All of the reactions of the pentose phosphate pathway occur in the cytoplasm, so the enzyme transketolase would remain in the homogenate described in the question stem while the other enzymes mentioned in the other answer choices would be removed because they all reside within the mitochondria."
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Old 03-24-2012
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Transketolase
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Old 03-24-2012
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Correct Answer

I follow with TRANSKETOLASE in HMP shunt
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Old 03-24-2012
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It's c,......for such question....always go for diagnosis of exclusion...see which pathwY the enzymes utilize and then...ans
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Old 03-26-2012
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Default C

I had this very same question on my exam and chose C
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