Transaldolase is a
Correct Answer: Transferase
Description: Transaldolase 1 is a key enzyme of the nonoxidative pentose phosphate pathway providing ribose-5-phosphate for nucleic acid synthesis and NADPH for lipid biosynthesis. This pathway can also maintain glutathione at a reduced state and thus protect sulfhydryl groups and cellular integrity from oxygen radicals. The residue of lysine-142 in the active site of transaldolase forms a Schiff base with the keto group in sedoheptulose-7-phosphate after deprotonation by another active site residue, glutamate-106. The reaction mechanism is similar to the reverse reaction catalyzed by aldolase: The bond joining carbons 3 and 4 is broken, leaving dihydroxyacetonejoined to the enzyme a Schiff base. This cleavage reaction generates the unusual aldose sugar erythrose-4-phosphate. Then transaldolase catalyzes the condensation of glyceraldehyde-3-phosphate with the Schiff base of dihydroxyacetone, yielding enzyme-bound fructose 6-phosphate. Hydrolysis of the Schiff base liberates free fructose 6-phosphate, one of the products of the pentose phosphate pathway.Ref: DM Vasudevan, Page no: 691
Category:
Biochemistry
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now