biosynthesis and degradation of nucleotides ©copyright 1999-2004 by gene c. lavers no part of this...
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Biosynthesis and Biosynthesis and Degradation of Degradation of Nucleotides Nucleotides
Biosynthesis and Biosynthesis and Degradation of Degradation of Nucleotides Nucleotides
©Copyright 1999-2004 by Gene C. Lavers
No part of this presentation may be reproduced by any mechanical, photographic, or electronic process, or in the form of a phonographic recording, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use, without written permission from the publisher.
©Copyright 1999-2004 by Gene C. Lavers
No part of this presentation may be reproduced by any mechanical, photographic, or electronic process, or in the form of a phonographic recording, nor may it be stored in a retrieval system, transmitted, or otherwise copied for public or private use, without written permission from the publisher.
Lecture 42-43Lecture 42-43Baynes & Dominiczak, Baynes & Dominiczak, Chapter 28Chapter 28
Gene C. Lavers, Ph.D.Gene C. Lavers, [email protected]@nyu.edu
Lecture 42-43Lecture 42-43Baynes & Dominiczak, Baynes & Dominiczak, Chapter 28Chapter 28
Gene C. Lavers, Ph.D.Gene C. Lavers, [email protected]@nyu.edu
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
2
Purine and Pyrimidine Purine and Pyrimidine Nucleic Acid Nucleic Acid MetabolismMetabolism Parent heterocyclic compoundsParent heterocyclic compounds
Purine and Pyrimidine Purine and Pyrimidine Nucleic Acid Nucleic Acid MetabolismMetabolism Parent heterocyclic compoundsParent heterocyclic compounds
Fig. 28.1 Structure of purines and pyrimidines.Fig. 28.1 Structure of purines and pyrimidines.Fig. 28.1 Structure of purines and pyrimidines.Fig. 28.1 Structure of purines and pyrimidines.
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
3
Purine and Pyrimidine Family Purine and Pyrimidine Family Nucleic Acid Nucleic Acid MetabolismMetabolism Bases, nucleosides, nucleotidesBases, nucleosides, nucleotides
Purine and Pyrimidine Family Purine and Pyrimidine Family Nucleic Acid Nucleic Acid MetabolismMetabolism Bases, nucleosides, nucleotidesBases, nucleosides, nucleotides
NN99-H -H N N–– + H + H++ basic N basic N Purines and pyrimidines are semi-Purines and pyrimidines are semi-
aromatic ring systemsaromatic ring systems bonds similar to benzenebonds similar to benzene Bases stack verticallyBases stack vertically
Ribose in RNA; deoxyribose in DNARibose in RNA; deoxyribose in DNA (d)(d)Base-sugar = Base-sugar = (d)(d)nucleosidenucleoside
(d)(d)Base-sugar-POBase-sugar-PO44== = = (d)(d)nucleotidenucleotide
Base-pairsBase-pairs A A = = T or T T or T = = A AA A==U or UU or U==A A
C C G or G G or G CC
A C G U are in RNAA C G U are in RNA dA dC dG dT are in DNAdA dC dG dT are in DNA
NN99-H -H N N–– + H + H++ basic N basic N Purines and pyrimidines are semi-Purines and pyrimidines are semi-
aromatic ring systemsaromatic ring systems bonds similar to benzenebonds similar to benzene Bases stack verticallyBases stack vertically
Ribose in RNA; deoxyribose in DNARibose in RNA; deoxyribose in DNA (d)(d)Base-sugar = Base-sugar = (d)(d)nucleosidenucleoside
(d)(d)Base-sugar-POBase-sugar-PO44== = = (d)(d)nucleotidenucleotide
Base-pairsBase-pairs A A = = T or T T or T = = A AA A==U or UU or U==A A
C C G or G G or G CC
A C G U are in RNAA C G U are in RNA dA dC dG dT are in DNAdA dC dG dT are in DNA
D + OD + O2 2 D + OD + O2 2
Fig. 28.2 Names of purine and pyrimidines.Fig. 28.2 Names of purine and pyrimidines.Fig. 28.2 Names of purine and pyrimidines.Fig. 28.2 Names of purine and pyrimidines.
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Metabolic RolesMetabolic Roles Nucleic Acid Nucleic Acid MetabolismMetabolismNucleotides IntroductionIntroduction
Metabolic RolesMetabolic Roles Nucleic Acid Nucleic Acid MetabolismMetabolismNucleotides IntroductionIntroduction
DNA and RNA Synthesis DNA and RNA Synthesis dNTP, NTPdNTP, NTP
Protein Synthesis Protein Synthesis ATP, GTPATP, GTP
Glycogen Synthesis Glycogen Synthesis UDP-glucoseUDP-glucose
Oxidative Phosphorylation Oxidative Phosphorylation ADP/ATPADP/ATP
Signal Transduction Signal Transduction cAMP cGMPcAMP cGMP
Muscle Contraction Muscle Contraction ATPATP
Electrolyte Balance Electrolyte Balance ATPATP
CoenzymesCoenzymes NAD FAD CoANAD FAD CoA
Allosteric regulatorsAllosteric regulators ATP, AMP … ATP, AMP …
DNA and RNA Synthesis DNA and RNA Synthesis dNTP, NTPdNTP, NTP
Protein Synthesis Protein Synthesis ATP, GTPATP, GTP
Glycogen Synthesis Glycogen Synthesis UDP-glucoseUDP-glucose
Oxidative Phosphorylation Oxidative Phosphorylation ADP/ATPADP/ATP
Signal Transduction Signal Transduction cAMP cGMPcAMP cGMP
Muscle Contraction Muscle Contraction ATPATP
Electrolyte Balance Electrolyte Balance ATPATP
CoenzymesCoenzymes NAD FAD CoANAD FAD CoA
Allosteric regulatorsAllosteric regulators ATP, AMP … ATP, AMP …
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
5
PRPP used in other RxPRPP used in other Rx
1.1. 1PR1PRPP + NHPP + NH22 PR PRNHNH22
2.2. Amide with gly; ATP usedAmide with gly; ATP used
3.3. 1-carbon (C1-carbon (C88) N) N1010-THFA-THFA
4.4. Gln Gln amidine (N amidine (N33))
5.5. Ring-closure – HRing-closure – H22OO
6.6. COCO22 (C (C66))
7.7. Asp (NAsp (N11) [i.e., urea cycle]) [i.e., urea cycle]
8.8. fumaratefumarate
9.9. 1-carbon (C1-carbon (C22) N) N1010-THFA-THFA
10.10. Ring-closure – HRing-closure – H22O O
PRPP used in other RxPRPP used in other Rx
1.1. 1PR1PRPP + NHPP + NH22 PR PRNHNH22
2.2. Amide with gly; ATP usedAmide with gly; ATP used
3.3. 1-carbon (C1-carbon (C88) N) N1010-THFA-THFA
4.4. Gln Gln amidine (N amidine (N33))
5.5. Ring-closure – HRing-closure – H22OO
6.6. COCO22 (C (C66))
7.7. Asp (NAsp (N11) [i.e., urea cycle]) [i.e., urea cycle]
8.8. fumaratefumarate
9.9. 1-carbon (C1-carbon (C22) N) N1010-THFA-THFA
10.10. Ring-closure – HRing-closure – H22O O
Purine synthesis Purine synthesis Nucleic Acid Nucleic Acid MetabolismMetabolism Ten steps ( 5 + 5) Ten steps ( 5 + 5) IMP IMP CytoplasmCytoplasm
Purine synthesis Purine synthesis Nucleic Acid Nucleic Acid MetabolismMetabolism Ten steps ( 5 + 5) Ten steps ( 5 + 5) IMP IMP CytoplasmCytoplasm
Fig. 28.3 Metabolic pathway forFig. 28.3 Metabolic pathway for synthesis of purinessynthesis of purinesFig. 28.3 Metabolic pathway forFig. 28.3 Metabolic pathway for synthesis of purinessynthesis of purines
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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IMP IMP AMP and GMP AMP and GMP Nucleic Acid Nucleic Acid MetabolismMetabolism Branched pathway Branched pathway CytoplasmCytoplasm
IMP IMP AMP and GMP AMP and GMP Nucleic Acid Nucleic Acid MetabolismMetabolism Branched pathway Branched pathway CytoplasmCytoplasm
IMP common precursor for AMP and GMPIMP common precursor for AMP and GMP AMPAMP
– GTP (GDP) cross-substrate for AMP synthesisGTP (GDP) cross-substrate for AMP synthesis
– Adenylosuccinate similar to urea cycle compoundAdenylosuccinate similar to urea cycle compound fumarate + AMPfumarate + AMP
GMPGMP– Oxidation (NADOxidation (NAD++) yields xanthine-5’P (XMP)) yields xanthine-5’P (XMP)
– ATP (AMP + PPATP (AMP + PP2Pi) amination (gln) amide yields 2Pi) amination (gln) amide yields GMPGMP
Energy costEnergy cost– IMP synthesis costs 4 ATPIMP synthesis costs 4 ATP
– AMP synthesis costs GTP (or 5 high energy bonds)AMP synthesis costs GTP (or 5 high energy bonds)
– GMP synthesis costs ATP (or 6 high energy bonds)GMP synthesis costs ATP (or 6 high energy bonds) Purine synthesis is proportional: A > GPurine synthesis is proportional: A > G PhosphorylationsPhosphorylations
– AMP AMP ADP ADP ATP ATP
– GMP GMP GDP GDP GTP GTP
IMP common precursor for AMP and GMPIMP common precursor for AMP and GMP AMPAMP
– GTP (GDP) cross-substrate for AMP synthesisGTP (GDP) cross-substrate for AMP synthesis
– Adenylosuccinate similar to urea cycle compoundAdenylosuccinate similar to urea cycle compound fumarate + AMPfumarate + AMP
GMPGMP– Oxidation (NADOxidation (NAD++) yields xanthine-5’P (XMP)) yields xanthine-5’P (XMP)
– ATP (AMP + PPATP (AMP + PP2Pi) amination (gln) amide yields 2Pi) amination (gln) amide yields GMPGMP
Energy costEnergy cost– IMP synthesis costs 4 ATPIMP synthesis costs 4 ATP
– AMP synthesis costs GTP (or 5 high energy bonds)AMP synthesis costs GTP (or 5 high energy bonds)
– GMP synthesis costs ATP (or 6 high energy bonds)GMP synthesis costs ATP (or 6 high energy bonds) Purine synthesis is proportional: A > GPurine synthesis is proportional: A > G PhosphorylationsPhosphorylations
– AMP AMP ADP ADP ATP ATP
– GMP GMP GDP GDP GTP GTP
D + OD + O2 2 D + OD + O2 2
Fig. 28.4 Conversion of IMP to AMP and GMP.Fig. 28.4 Conversion of IMP to AMP and GMP.Fig. 28.4 Conversion of IMP to AMP and GMP.Fig. 28.4 Conversion of IMP to AMP and GMP.
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Purine synthesis Purine synthesis Nucleic Acid Nucleic Acid MetabolismMetabolism Control and Salvage of IMP, AMP and GMP Salvage of IMP, AMP and GMP CytoplasmCytoplasm
Purine synthesis Purine synthesis Nucleic Acid Nucleic Acid MetabolismMetabolism Control and Salvage of IMP, AMP and GMP Salvage of IMP, AMP and GMP CytoplasmCytoplasm
Control of Purine SynthesisControl of Purine Synthesis Product inhibition by AMP and GMP from IMPProduct inhibition by AMP and GMP from IMP Cross-nucletide co-substrates required Cross-nucletide co-substrates required balanced synthesis balanced synthesis Allosteric feedback inhibition of Allosteric feedback inhibition of PRPP-Gln amidotransferasePRPP-Gln amidotransferase
Salvage of free basesSalvage of free bases Nucleosides and nucleotides spontaneously hydrolyze N-Nucleosides and nucleotides spontaneously hydrolyze N--glycosidic bond -glycosidic bond
free base released free base released catabolized to urate catabolized to urate De novoDe novo synthesis of purines minimized by 1-step conversion back to synthesis of purines minimized by 1-step conversion back to
nucleoside-5’Pnucleoside-5’P– Adenine + PRPP Adenine + PRPP AMP via AMP via A-PRTaseA-PRTase– Hypoxanthine + PRPP Hypoxanthine + PRPP IMP via IMP via H-PRTaseH-PRTase– Guanine + PRPP Guanine + PRPP GMP GMP H-PRTaseH-PRTase
Gout and Lesch-Nyhan syndromesGout and Lesch-Nyhan syndromes Salvage enzymes deficient (0.1% in brain gives Lesch-Nyhan psychiatric Salvage enzymes deficient (0.1% in brain gives Lesch-Nyhan psychiatric
behavior)behavior)– Up to 5-fold extra Up to 5-fold extra de novode novo synthesis leads to excessive accumulation of urate. synthesis leads to excessive accumulation of urate.– Urate is sparingly soluble; needle crystals form in joints and kidneys Urate is sparingly soluble; needle crystals form in joints and kidneys gouty arthritis gouty arthritis
and kidney damage. Untreated L-N children die in teenage years – renal damage and kidney damage. Untreated L-N children die in teenage years – renal damage failure.failure.
Treatment: inhibition (Treatment: inhibition (XX) of ) of XOXO by allopurinol prevents excessive purine base by allopurinol prevents excessive purine base catabolism to urate, i.e., ade catabolism to urate, i.e., ade hyp hyp ——XX xan xan ——XX urate (Fig 28.5), thereby urate (Fig 28.5), thereby limiting excessive purine synthesis that occurs in untreated patientslimiting excessive purine synthesis that occurs in untreated patients
Control of Purine SynthesisControl of Purine Synthesis Product inhibition by AMP and GMP from IMPProduct inhibition by AMP and GMP from IMP Cross-nucletide co-substrates required Cross-nucletide co-substrates required balanced synthesis balanced synthesis Allosteric feedback inhibition of Allosteric feedback inhibition of PRPP-Gln amidotransferasePRPP-Gln amidotransferase
Salvage of free basesSalvage of free bases Nucleosides and nucleotides spontaneously hydrolyze N-Nucleosides and nucleotides spontaneously hydrolyze N--glycosidic bond -glycosidic bond
free base released free base released catabolized to urate catabolized to urate De novoDe novo synthesis of purines minimized by 1-step conversion back to synthesis of purines minimized by 1-step conversion back to
nucleoside-5’Pnucleoside-5’P– Adenine + PRPP Adenine + PRPP AMP via AMP via A-PRTaseA-PRTase– Hypoxanthine + PRPP Hypoxanthine + PRPP IMP via IMP via H-PRTaseH-PRTase– Guanine + PRPP Guanine + PRPP GMP GMP H-PRTaseH-PRTase
Gout and Lesch-Nyhan syndromesGout and Lesch-Nyhan syndromes Salvage enzymes deficient (0.1% in brain gives Lesch-Nyhan psychiatric Salvage enzymes deficient (0.1% in brain gives Lesch-Nyhan psychiatric
behavior)behavior)– Up to 5-fold extra Up to 5-fold extra de novode novo synthesis leads to excessive accumulation of urate. synthesis leads to excessive accumulation of urate.– Urate is sparingly soluble; needle crystals form in joints and kidneys Urate is sparingly soluble; needle crystals form in joints and kidneys gouty arthritis gouty arthritis
and kidney damage. Untreated L-N children die in teenage years – renal damage and kidney damage. Untreated L-N children die in teenage years – renal damage failure.failure.
Treatment: inhibition (Treatment: inhibition (XX) of ) of XOXO by allopurinol prevents excessive purine base by allopurinol prevents excessive purine base catabolism to urate, i.e., ade catabolism to urate, i.e., ade hyp hyp ——XX xan xan ——XX urate (Fig 28.5), thereby urate (Fig 28.5), thereby limiting excessive purine synthesis that occurs in untreated patientslimiting excessive purine synthesis that occurs in untreated patients
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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AzaserineAzaserine Purine Nucleotide Purine Nucleotide BiosynthesisBiosynthesis Diazo-containing AntibioticsDiazo-containing Antibiotics ClinicalClinical
AzaserineAzaserine Purine Nucleotide Purine Nucleotide BiosynthesisBiosynthesis Diazo-containing AntibioticsDiazo-containing Antibiotics ClinicalClinical
1. Glutamine analogs as affinity labels.1. Glutamine analogs as affinity labels. AzaserineAzaserine and and 6-diazo-5-oxo-norleucine6-diazo-5-oxo-norleucine
2. Diazo-containing antibiotics bind in active site of 2. Diazo-containing antibiotics bind in active site of amidotransferase. Diazo group alkylation of nucleophilic amidotransferase. Diazo group alkylation of nucleophilic cysteine residue in enzyme’s active site.cysteine residue in enzyme’s active site.
3. Expect many enzymes with Gln as substrate would be 3. Expect many enzymes with Gln as substrate would be inactivated by diazo-containing antibiotics. inactivated by diazo-containing antibiotics.
1. Glutamine analogs as affinity labels.1. Glutamine analogs as affinity labels. AzaserineAzaserine and and 6-diazo-5-oxo-norleucine6-diazo-5-oxo-norleucine
2. Diazo-containing antibiotics bind in active site of 2. Diazo-containing antibiotics bind in active site of amidotransferase. Diazo group alkylation of nucleophilic amidotransferase. Diazo group alkylation of nucleophilic cysteine residue in enzyme’s active site.cysteine residue in enzyme’s active site.
3. Expect many enzymes with Gln as substrate would be 3. Expect many enzymes with Gln as substrate would be inactivated by diazo-containing antibiotics. inactivated by diazo-containing antibiotics.
OOOO
OHOHOHOH
OOOO
HH22NNHH22NN
NHNH22
OOOO
OHOHOHOH
OOOO
N=N=CN=N=C HHN=N=CN=N=C HH
NHNH22NHNH22
OOOO
OOOO
OHOHOHOH
OOOO
N=N=CN=N=C HHN=N=CN=N=C HH
NHNH22
glutamineglutamineglutamineglutamine azaserineazaserineazaserineazaserine 6-diazo-5-oxo-norleucine6-diazo-5-oxo-norleucine6-diazo-5-oxo-norleucine6-diazo-5-oxo-norleucine
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Catabolism of Purines Catabolism of Purines Nucleic Acid Nucleic Acid MetabolismMetabolism Allopurinol treatment of gout and Lesch-Nyhan syndromesAllopurinol treatment of gout and Lesch-Nyhan syndromes
Catabolism of Purines Catabolism of Purines Nucleic Acid Nucleic Acid MetabolismMetabolism Allopurinol treatment of gout and Lesch-Nyhan syndromesAllopurinol treatment of gout and Lesch-Nyhan syndromes
Fig. 28.5 Inhibition of xanthine oxidase (XO) Fig. 28.5 Inhibition of xanthine oxidase (XO) by by alloxanthine is the mechanism involved alloxanthine is the mechanism involved in in allopurinol treatment of gout and allopurinol treatment of gout and Lesch-Lesch- Nyhan syndromes.Nyhan syndromes.
Fig. 28.5 Inhibition of xanthine oxidase (XO) Fig. 28.5 Inhibition of xanthine oxidase (XO) by by alloxanthine is the mechanism involved alloxanthine is the mechanism involved in in allopurinol treatment of gout and allopurinol treatment of gout and Lesch-Lesch- Nyhan syndromes.Nyhan syndromes.
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Pyrimidine Synthesis Pyrimidine Synthesis Nucleic Acid Nucleic Acid MetabolismMetabolism Multifunctional enzymes, CAD and UMP synthaseMultifunctional enzymes, CAD and UMP synthase
Pyrimidine Synthesis Pyrimidine Synthesis Nucleic Acid Nucleic Acid MetabolismMetabolism Multifunctional enzymes, CAD and UMP synthaseMultifunctional enzymes, CAD and UMP synthase
CP made by carbamoyl phosphate synthetaseCP made by carbamoyl phosphate synthetase
different from different from CPSCPS that makes CP in urea that makes CP in urea
cycle.cycle. In prokaryotes individual enzymesIn prokaryotes individual enzymes In eukaryotes 3 + 2 multifunctional enzymesIn eukaryotes 3 + 2 multifunctional enzymes
Dihydroorotate dehydrogenaseDihydroorotate dehydrogenase linked to ETS linked to ETS
via ubiquinone via ubiquinone 2 ATP. 2 ATP. Dihydroorotate oxidized to orotate by Dihydroorotate oxidized to orotate by
mitochondrial enzyme.mitochondrial enzyme. PPRP + orotate PPRP + orotate orotate nucleotide orotate nucleotide UMP + UMP +
COCO22
UMP UMP UDP UDP UTP (gln) UTP (gln) CTP CTP
CP made by carbamoyl phosphate synthetaseCP made by carbamoyl phosphate synthetase
different from different from CPSCPS that makes CP in urea that makes CP in urea
cycle.cycle. In prokaryotes individual enzymesIn prokaryotes individual enzymes In eukaryotes 3 + 2 multifunctional enzymesIn eukaryotes 3 + 2 multifunctional enzymes
Dihydroorotate dehydrogenaseDihydroorotate dehydrogenase linked to ETS linked to ETS
via ubiquinone via ubiquinone 2 ATP. 2 ATP. Dihydroorotate oxidized to orotate by Dihydroorotate oxidized to orotate by
mitochondrial enzyme.mitochondrial enzyme. PPRP + orotate PPRP + orotate orotate nucleotide orotate nucleotide UMP + UMP +
COCO22
UMP UMP UDP UDP UTP (gln) UTP (gln) CTP CTP
Fig. 28.6 Metabolic pathway for the Fig. 28.6 Metabolic pathway for the synthesis of synthesis of pyrimidines. pyrimidines.Fig. 28.6 Metabolic pathway for the Fig. 28.6 Metabolic pathway for the synthesis of synthesis of pyrimidines. pyrimidines.
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Biosynthesis of CTP and TTP Biosynthesis of CTP and TTP Nucleic Acid Nucleic Acid MetabolismMetabolism THFA vs. DHFA and chemotherapyTHFA vs. DHFA and chemotherapy CytosolCytosol
Biosynthesis of CTP and TTP Biosynthesis of CTP and TTP Nucleic Acid Nucleic Acid MetabolismMetabolism THFA vs. DHFA and chemotherapyTHFA vs. DHFA and chemotherapy CytosolCytosol
Fig. 28.7 Synthesis Fig. 28.7 Synthesis of pyrimidine of pyrimidine triphosphates.triphosphates.
Inhibited at the Inhibited at the indicated sites by indicated sites by
• fluorodeoxyuridylate fluorodeoxyuridylate (FdUMP) (FdUMP)
• methotrexatemethotrexate• aminopterin aminopterin • trimethoprimtrimethoprim
Fig. 28.7 Synthesis Fig. 28.7 Synthesis of pyrimidine of pyrimidine triphosphates.triphosphates.
Inhibited at the Inhibited at the indicated sites by indicated sites by
• fluorodeoxyuridylate fluorodeoxyuridylate (FdUMP) (FdUMP)
• methotrexatemethotrexate• aminopterin aminopterin • trimethoprimtrimethoprim
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Ribose to DeoxyriboseRibose to Deoxyribose Nucleic Acid Nucleic Acid MetabolismMetabolismRibonucleotide reductaseRibonucleotide reductase CytoplasmCytoplasm
Ribose to DeoxyriboseRibose to Deoxyribose Nucleic Acid Nucleic Acid MetabolismMetabolismRibonucleotide reductaseRibonucleotide reductase CytoplasmCytoplasm
OOOO
OHOHOHOH HHHH
PPPPOOPPPPOOBaseBaseBaseBase
22OOOO
OHOHOHOH OHOHOHOH
PPPPOOPPPPOOBaseBaseBaseBase
22
HH++ + + NADPNADPHHHH++ + + NADPNADPHH NADPNADP++NADPNADP++
Glutathione reductaseGlutathione reductaseGlutathione reductaseGlutathione reductase
GlutathioneGlutathioneGlutathioneGlutathione
GlutaredoxinGlutaredoxinGlutaredoxinGlutaredoxin
Ribonucleotide reductaseRibonucleotide reductaseRibonucleotide reductaseRibonucleotide reductase
FADFADFADFAD FADFADHH22FADFADHH22
Thioredoxin reductaseThioredoxin reductaseThioredoxin reductaseThioredoxin reductase
ThioredoxinThioredoxinThioredoxinThioredoxin
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
13
Uracil to Thymine: 1-carbon fragment on folate Uracil to Thymine: 1-carbon fragment on folate Deoxy Deoxy Nucleic Acids Nucleic Acids Dihydrofolate: dead-end metabolite Dihydrofolate: dead-end metabolite EnzymologyEnzymology
Uracil to Thymine: 1-carbon fragment on folate Uracil to Thymine: 1-carbon fragment on folate Deoxy Deoxy Nucleic Acids Nucleic Acids Dihydrofolate: dead-end metabolite Dihydrofolate: dead-end metabolite EnzymologyEnzymology
dUMPdUMPdUMPdUMP dTMdTMPP
dTMdTMPP
TMP synthaseTMP synthaseTMP synthaseTMP synthase
NN55,N,N1010--CHCH22-FH-FH44NN55,N,N1010--CHCH22-FH-FH44
FHFH22FHFH22
FHFH44FHFH44
NADPNADPHH + + H+H+NADPNADPHH + + H+H+
NADPNADP++NADPNADP++
Glc6PGlc6P
Pentose Pentose ShuntShunt
Pentose Pentose ShuntShunt
Rib5PRib5P
serineserineserineserine
glycineglycineglycineglycine3. Serine Serine hydroxymethhydroxymethyl yl transferasetransferase
3. Serine Serine hydroxymethhydroxymethyl yl transferasetransferase
cytoplasmcytoplasmcytoplasmcytoplasm
1111
2. Dihydrofolate2. Dihydrofolatereductasereductase2. Dihydrofolate2. Dihydrofolatereductasereductase
Fudr (fluorodeoxyuridate)Fudr (fluorodeoxyuridate)
aminopterinaminopterinmethotrexatemethotrexate(amethopterin)(amethopterin)
aminopterinaminopterinmethotrexatemethotrexate(amethopterin)(amethopterin)
Suicide inhibitorSuicide inhibitorSuicide inhibitorSuicide inhibitor
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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DHFA ReductaseDHFA Reductase Deoxy Nucleic Deoxy Nucleic AcidsAcidsChemotherapyChemotherapy EnzymologyEnzymology
DHFA ReductaseDHFA Reductase Deoxy Nucleic Deoxy Nucleic AcidsAcidsChemotherapyChemotherapy EnzymologyEnzymology
cytoplasmcytoplasmcytoplasmcytoplasm
NN55NN1010methyleneTHFAmethyleneTHFANN55NN1010methyleneTHFAmethyleneTHFA
NNNN
NNNN NNNN
HH22NNHH22NN NNNN
NNNNHOHOHOHO
5555
10101010
HHHH
HHHH
HH22CCHH22CC
OOOO
((GluGlu))nn((GluGlu))nn
HHHH
NNNN
NNNN NNNN
HH22NNHH22NN NNNN
NNNNHOHOHOHO
5555
10101010
HHHH
OOOO
(Glu)(Glu)(Glu)(Glu)
DHFADHFADHFADHFADihydrofolateDihydrofolateDihydrofolateDihydrofolate
Thymidylate synthaseThymidylate synthaseThymidylate synthaseThymidylate synthase
dUMPdUMPdUMPdUMP dTMPdTMPdTMPdTMP
R = H, aminopterinR = H, aminopterinR = H, aminopterinR = H, aminopterinR = CHR = CH33, methotrexate, methotrexateR = CHR = CH33, methotrexate, methotrexate
trimethoprimtrimethoprim
HNHNHNHN
HH22NNHH22NN NNNN
NHNH22NHNH22
OCHOCH33OCHOCH33
OCHOCH33OCHOCH33
OCHOCH33OCHOCH33NNNN
NNNN NNNN
HH22NNHH22NN NNNN
NNNNNHNH22NHNH22
5555
10101010
HHHH
RRRR ((gluglu))nn((gluglu))nn
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
15
Deoxyribose and ThymineDeoxyribose and Thymine Nucleic Acid Nucleic Acid MetabolismMetabolism
OverviewOverview
Deoxyribose and ThymineDeoxyribose and Thymine Nucleic Acid Nucleic Acid MetabolismMetabolism
OverviewOverview
cytoplasmcytoplasm cytoplasmcytoplasm
NMPNMPNMPNMP
NDPNDPNDPNDP
NTPNTPNTPNTP
RibonucleosideRibonucleoside bisphosphatebisphosphate
reductasereductase
RibonucleosideRibonucleoside bisphosphatebisphosphate
reductasereductasedNDPdNDP dNTPdNTP
riboseriboseriboseribose deoxyribosedeoxyribose
dATPdATP
dCTPdCTP
dGTPdGTP
dUTPdUTPdUTPdUTPdUMPdUMP
1111
22
dTMPdTMP
TMP TMP synthasesynthase
TMP TMP synthasesynthase
dTTPdTTP
pppppppp
DNADNADNADNA
DNADNADNADNA
DNADNADNADNA
DNADNADNADNA
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Synthesis, Synthesis, Catabolism,Catabolism, SalvageSalvage Pyrimidine Pyrimidine Metabolism Metabolism OverviewOverview
Synthesis, Synthesis, Catabolism,Catabolism, SalvageSalvage Pyrimidine Pyrimidine Metabolism Metabolism OverviewOverview
““OMP”OMP”““OMP”OMP”
UraUraUraUra
OrotateOrotateOrotateOrotate
UMPUMPUMPUMP
ThyThyThyThy
3 steps3 steps3 steps3 steps
PRPPPRPPC.P.C.P.C.P.C.P. AspAspAspAsp
CTPCTPCTPCTP
2 Pi
1 enzyme1 enzyme1 enzyme1 enzyme
COCO22
UTPUTPUTPUTP
UDPUDPUDPUDP dUDPdUDPdUDPdUDP dUMPdUMPdUMPdUMP dTMPdTMPdTMPdTMP
RNARNA
-Ala-Ala-Ala-Ala 2-MeBu2-MeBu2-MeBu2-MeBu
CytCytCytCyt
??
dTTPdTTPdTTPdTTP
PPi
GlycogenGlycogen
DNA
DNA
UrdUrdUrdUrd ThdThdThdThdCydCydCydCyd
©Copyright 1999-2004 by Gene C. Lavers, Ph.D.
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Biosynthesis and Degradation Biosynthesis and Degradation
of Nucleotidesof Nucleotides
Biosynthesis and Degradation Biosynthesis and Degradation
of Nucleotidesof Nucleotides
ENDENDENDEND