Nucleotide Metabolism

Amino acid are precursors to

immune system signals, hormones, membrane lipid constituent, electron carriers, nucleotide bases

base + sugar is a

nucleoside

base + sugar + phosphate is a

nucleotide

Uracil is found in ____ only; Thymidine is found in _____ only

RNA, DNA

What are the amino acids that makes up the purine rings

Glycine, Glutamine, Aspartate (GQD)

What are the amino acids that makes up pyrimidine ring

Glutamine, Aspartate (QD)

N10-Formyl tetrahydrofolate provides carbon in the structure of ______ rings

purine

How many Carbon atoms does N10-Formyl tetrahydrofolate provide in the structure of purine rings?

2 at C2 and C8

PRPP → 5-phosphoribosyl-1-amine; what is enzyme?

glutamine phosphoribosyl amidotransferase

glutamine phosphoribosyl amidotransferase is the enzyme that converts what to what?

PRPP → 5-phosphoribosyl-1-amine

When PRPP → 5-phosphoribosyl-1-amine using the enzyme glutamine phosphoribosyl amidotransferase, ______ is converted to ____ (Amino acids)

glutamine to glutamate (q→e)

When PRPP → 5-phosphoribosyl-1-amine using the enzyme glutamine phosphoribosyl amidotransferase, ammonia is released from hydrolyzed glutamine and the ammonia displaces the _____ group(PPi)

pyrophophate

What is the product of 5-phosphoribosyl-1-amine after 9 steps?

Inosinate (IMP)

IMP reacts with adenine to form ______ which is converted to _____

• fumarate leaves

adenylosuccinate, adenylate (AMP)

IMP reduce NAD→ NADH to form ____ which is converted to _____

• q→e

xanthylate, guanylate (GMP)

List the two salvage enzymes

adenine phosphoribosyltransferase, HGPRT

adenine phosphoribosyltransferase is a salvage enzyme that works on

adenine + PRPP → adenylate + PPi

HGPRT is a salvage enzyme that works on

guanine + PRPP → Guanylate +PPi; hypoxanthine + PRPP → inosinate + PPi

In pyrimidine synthesis, which amino acid is the nitrogen donor?

Glutamine, Q

Pyrimidine synthesis step 1

bicarbonate → carbamoyl phosphate via CPS II

Pyrimidine synthesis step 2

carbamoyl phosphate → carbamoyl aspartate via ATCase

Pyrimidine synthesis step 3

carbamoyl aspartate → dihydroorotate → orotate

Pyrimidine synthesis step 4

orotate + PRPP → orotidylate

Pyrimidine synthesis step 5

orotidylate → UMP via orotidylate decarboxylase

the enzyme ____ concerts UTP to CTP

cytidylate synthetase

when UTP → CTP, what is source of NH3?

Glutamine Q

Identify the enzyme responsible for salvaging thymine during DNA degradation

Thymidine phosphorylase

Identify the enzyme responsible for generating thymine nucleotides

Thymidine Kinase

In the production of deoxyribonucleotides from ribonucleotides, What is the key enzyme?

nucleotide reductase

In the production of deoxyribonucleotides from ribonucleotide, where is the H atoms coming from?

NADPH

What are the proteins involved in redox pathway used to produce of deoxyribonucleotides from ribonucleotide?

thioredoxin and glutaredoxin

thymidylate synthase is the enzyme in the production

dUMP + N5N10MethyleneTHF → dTMP + DHF

Explain the step catalyzed by DHFR (dihydrofolate reductase) enzyme.

dihydrofolate → tetrahydrofolate

Identify the drug that inhibits xanthine oxidase, as an anti-gout agent.

Allopurinol

Chemotherapeutic agents that inhibits glutamine amidotransferase

Glutamine analogs (azaserine, acivicin)

Chemotherapeutic agents that inhibits thymidylate synthase

Fluorouracil → fDUMP

Chemotherapeutic agents that are DHFR inhibitors

methotrexate, aminopterin, trimethoprim