Multiple choice

Match the enzymes in column I with the respective statements in column II.

Column I Column II
1. Dihydrofolate reductase A. Catalyses melanin production
2. Malate dehydrogenase B. Use NADPH for reducing a derivative of folic acid
3. Glycerol dehydrogenase C. Reduces oxaloacetate to malate
4. Tyrosinase D. Catalyses alanine cycle
5. Serum glutamic-pyruvic transaminase E. Zinc-dependent

  1. 1 - C, 2 - D, 3 - A, 4 - E, 5 - B

  2. 1 - D, 2 - C, 3 - E, 4 - B, 5 - A

  3. 1 - E, 2 - C, 3 - D, 4 - B, 5 - A

  4. 1 - B, 2 - C, 3 - E, 4 - A, 5 - D

  5. 1 - B, 2 - E, 3 - A, 4 - C, 5 - D
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Dihydrofolate reductase (DHFR) uses NADPH in the form of electron donor for reducing dihydrofolic acid, a derivative of folic acid, to tetrahydrofolic acid. In humans, DHFR is encoded by DHFR gene and located in chromosome 5’s q11→q22 region. Malate dehydrogenase is a mitochondrial enzyme which is used to reduce oxaloacetate to malate in gluconeogenesis. Glycerol dehydrogenase catalyses a chemical reaction which involves 2 substrates like NAD+ and glycerol and 3 products like NADH, glycerone and H+. Structural studies of glycerol dehydrogenase have revealed that it is zinc-dependent. Tyrosinase is a rate limiting enzyme which controls melanin production. Tyrosinase is involved in the hydroxylation of monophenol and also the conversion of o-diphenol to corresponding o-quinone. The active site of all tyrosinases contains one binuclear copper centre. Serum glutamic-pyruvic transaminase, also known as alanine transaminase is present in the plasma and in different body tissues. It is commonly linked with the liver and catalyses 2 parts of alanine cycle.

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