Question

Ribonucleotide reductase is central to nucleotide metabolism. Which statement is false regarding its role in nucleotide biosynthesis?

		Ribonucleotide reductase is the rate-limiting step for synthesis of NADH
		Ribonucleotide reductase removes a hydroxyl group from ribonucleotides
		Ribonucleotide reductase uses sulfur atoms to catalyze redox reactions
		The activity of ribonucleotide reductase is controlled by the abundance of substrates and allosteric effectors

Answer 1

First statement is incorrect because the rate limiting step in NADH synthesis is not ribonucleotide reductase.The steps are regulated by IDO and TDO

Second statement is true because the enzymes catalysed the removal of the 2’hydroxyl group from the ribose sugar of diphospahte nucleosides

Third statement is correct because the M1 component of the ribonucleotide reducatse consist of sulhydryl groups where the sulfur atoms are involved in the redox reactions.

Fourth statement is correct because increase in the substrate concentration as well as the effector binding to the allostetic site of the enzyme regulate it’s activity .

Therefore from the given statement a is the incorrect statement