Term
| 7 Roles of Nucleotides in the Cell |
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Definition
| Storage of Information(RNA/DNA), Formation of structures(Ribozymes), Source of Energy(ATP/GTP), Second messengers(cAMP), Switches(GTP-GDP hydrolysis and exchange), Protein Modification(ADP-phosphorylation), Coenzymes/Cofactors/Electron-Proton Carriers |
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Definition
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Term
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Definition
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Term
| Flavin Adenine Dinucleotide (FAD) structure |
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Definition
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Term
| Nicotinamide Adenine Dinucleotide (NAD+) |
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Definition
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Term
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Definition
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Term
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Definition
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Term
Substrate of Deoxyribonucleotide
synthesis |
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Definition
| Nucleoside diphosphates (NDPs) |
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Term
Enzymes of Deoxyribonucleotide
synthesis |
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Definition
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Term
| NDP -> dNDP overall difference between reactants and products |
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Definition
NDP has OH on C2 of ribose ring.
dNDP has H on C2 of ribose ring. |
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Term
| Committed step of DNA synthesis |
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Definition
| Reduction at 2'-position with ribonucleotide reductase |
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Term
| ribonucleotide reductase has how many subunits? What type of enzyme is this? |
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Definition
| 2 subunits: R1 (86kD) and R2 (43.5kD). It is an a2b2 enzyme. |
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Term
What type of control is the synthesis of
ribonucleotide reductase subunits under? |
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Definition
| cell cycle control (G1, S, G2, M) |
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Term
Where is the catalytic center for the
ribonucleotide reductase? |
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Definition
| between the two types of subunits (R1 and R2) |
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Term
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Definition
| A chemical that inhibits the active site tyrosine on the ribonucleotide reductase |
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Term
| What types of regulatory sites are there on the R1 subunit? |
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Definition
S: Specificity site
A: Activity Site |
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Term
| What binds the S site on the ribonucleotide reductase? purpose? |
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Definition
ATP: favors CDP or UDP in site C -> dCDP and dUDP -> dUMP -> dTMP -> dTTP
dATP,
dGTP: ADP in site C -> dATP,
dTTP: GDP or ADP in site C -> dGTP & dATP |
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Term
| What binds the A site on the ribonucleotide reductase |
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Definition
| ATP (RR ON), dATP (RR OFF) |
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Term
| What metal ion is present in the b subunit of the ribonucleotide reductase? |
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Definition
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Term
| What activates ribonucleotide reductase activity? |
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Definition
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Term
| What deactivates ribonucleotide reductase activity? |
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Definition
| dATP - overall deactivates |
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Term
To restore Ribonucleotide Reductase after reduction of
ribonucleotide substrate, there is a series of ___________ |
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Definition
oxidationreduction reactions involving ribonucleotide reductase,
thioredoxin, thioredoxin reductase, and NADPH. |
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Term
| Enzyme for thymidine synthesis |
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Definition
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Term
| Substrate for thymidine synthesis |
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Definition
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Term
| Reaction description of dUMP -> dTMP |
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Definition
| N5,N10methylene-THF donates methyl group to 5C of dUMP. This produces DHF which must be restored to THF. |
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Term
Restoration to convert DHF to THF uses the enzyme ______, followed by
conversion of THF to 5,10-Methylene THF using _________. |
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Definition
Dihyrdofolate Reductase (DHFR)
Serine Hydroxymethyl Transferase |
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Term
| Where do you get dUMP from? |
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Definition
dUDP -> dUTP -> dUMP -> dTMP
OR
dCDP -> dCMP (deaminate to) -> dUMP -> dTMP |
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Term
| dCMP deaminase reaction (substrate, enzyme, product) |
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Definition
| dCMP -(dCMP deaminase)-> dUMP |
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Term
| dCMP deaminase reaction's reactants and products with explanation |
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Definition
dCMP + H+ + H2O -> dUMP +NH4+
(NH2 is removed from pyrimidine carbon and replaced with O) |
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Term
| How is dCMP deaminase regulated? |
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Definition
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Term
| deamination of Cytosine gives _____ |
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Definition
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Term
Normally,
A pairs with _____
C pairs with _____
G pairs with _____
T pairs with _____
U pairs with _____ |
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Definition
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Term
| What is a problem that arises from deamination of dCTP? How is this dealt with in the cell? |
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Definition
U-G pair would result.
That has
to be excised by Uracil N-Glycosylase enzymes and replaced with C. |
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Term
| What is Tetrahydrofolate for? |
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Definition
| Folates are acceptors and donors of 1-C units. THF is the activated form. (used in dUMP -> dTMP) |
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Term
| Where is folic acid found? |
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Definition
| green plants, fresh fruits, yeast, and liver |
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Term
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Definition
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Term
| Folic acid is a combination of these three things |
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Definition
6-methyl pterin
PABA
Glutamate |
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Term
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Definition
a thymine analog that is converted to 5'-FUdylate by a PRPP-dependent phosphoribosyltransferase
and passes through the
reactions of dNTP synthesis,
becoming 2'-d-5-FU, a potent inhibitor of thymidylate synthase |
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Term
| What type of drug is 5-FC |
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Definition
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Term
| What type of drug is 5-Fluoroorotate (5-FO)? |
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Definition
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Term
| What effect would targeting thymidylate synthase have on an organism? |
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Definition
| inhibited DNA replication and therefore inhibited cell growth |
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Term
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Definition
| an anti-tumor agent, acts as an irreversible inhibitor of glutamine-dependent enzymes by covalently attaching to nucleophilic groups in the glutamine-binding site |
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Term
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Definition
| Azaserine- a glutamine look-alike |
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Term
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Definition
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Term
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Definition
assay organism that will grow if supplied with T plus either A or G or
hypoxanthine or xanthine |
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Term
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Definition
analog of hypoxanthine, and therefore inhibitor of xanthine oxidase which degrades azathioprine (an antimetabolite)
Serves in combination with azathioprine as an antiviral drug.
Also, used to treat gout. |
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Term
| azathioprine is an example of _________ |
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Definition
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Term
| Retrovir (aka azidothymidine (AZT)) |
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Definition
| nucleotide analog used in HIV treatment |
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Term
| In binding with xanthine oxidase, allopurinol prevents what product from forming? |
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Definition
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Term
| What does purine catabolism lead to? |
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Definition
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Term
| What's the difference between nucleosides and nucleotides? |
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Definition
| nucleotides have 5'-P. Nucleosides do not. |
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Term
| Enzymes of AMP catabolism |
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Definition
| Nucleotidase, adenosine deaminase, Purine nucleoside phoshorylase (PNP), xanthine oxidase (x2) |
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Term
| Enzymes of GMP catabolism |
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Definition
| Nucleotidase, Purine nucleoside phoshorylase (PNP), Guanine deaminase xanthine oxidase |
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Term
| severe combined immunodeficiency syndrome (SCID) |
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Definition
| caused by Adenosine deaminase (ADA) deficiency. Can't convert AMP to IMP. |
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Term
| Further process of Uric acid |
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Definition
| Allantoin, allantoic acid(teleost fish), urea (cartilaginous fish and amphibians), ammonia (marine invertebrates) |
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Term
| Pyrimidine degragation: major products |
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Definition
C and U -> b-alanine + NH4+ + CO2
T -> b-aminoisobutyric acid + NH4+ + CO2 |
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Term
| What percentage of purine bases are salvaged? |
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Definition
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Term
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Definition
| G + a-PRPP -(HGPRT)-> GMP + PPi |
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Term
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Definition
| inability to salvage purines because of lack of HGPRT (enzyme in salvage reaction). |
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Term
In humans, pyrimidines are recycled from
nucleosides (what does this mean?) |
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Definition
phosphorylated so that they can
reenter the pool of usable pyrimidines |
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Term
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Definition
cause: accumulation of uric acid crystals in extremities (i.e. during chemotherapy with release of nucleic acids from tumor cells)
Xanthine oxidase can oxides hypoxanthine (2x) to uric acid
Allopurinol -(XO)-> oxypurinol (inhibits XO) is treatment |
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