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75 Cards in this Set
- Front
- Back
difference between a nucleotide and a nucleoside
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nucleosides: base and sugar
nucleotide: base, phosphate, and a sugar |
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linkage that binds a phosphate
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ester linkage to Carbon 5 on sugar
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two types of sugar
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ribose
deoxyribose |
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difference between the sugars
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has an OH on the carbon 2 position instead of a H
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linkage that binds the base
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N glycosidic bond
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name the purines
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Adenine and Guanine
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name the pyrimidines
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Cytosine, Thymine, and Uracil
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basic nucleotide funciton
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1) DNA Synthesis
2) RNA synthesis 3) transfer of highenergy groups 4) Component enzymes 5) regulatory molecules |
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purine ring structure
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physical notecard
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origins of purine ring
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1) Aspartate
2) N10 FTHF 3) amide N of glutamine 4) N10 FTHF 5) glycine 6) CO2 |
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Steps in Purine Synthesis
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1) R5P
2) PRPP 3) PAR 4) GAR 5) FGAR 6) FGAM 7) AIR 8) CAIR 9) SAICAR 10) AICAR 11) FAICAR 12) IMP |
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1) Purine
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PRPP synthetase
hydrolysis of ATP--> AMP |
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2) Purine
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Glutamine-PRPP amidotransferase
glutamine + H20 --> Glutamate + PP1 |
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3) Purine
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adition of glycine
hydrolysis of ATP --> ADP + Pi |
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4) Purine
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addition of N10formyl tetrahydroflourate
goes to THF |
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5) Purine
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Glutamine + ATP --> Glutamate + ADP + Pi
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6) Purine
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ATP --> ADP _Pi
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7) Purine
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addition of CO2
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8) Purine
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addition of aspartate
ATP --> ADP + Pi |
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9) Purine
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fumerate leaves
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10) Purine
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N10 formyl tetrahedral flourate goes to THF
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11) Purine
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bye bye H20
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IMP pathway
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draw pathway
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1) IMP
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Adenylsuccinate synthetase
IMP--> Adenylsuccinate addition of aspartate GTP --> GDP + Pi regulated by GTP |
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2) IMP
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Adenylsuccinase lyase
bye bye fumerate adenylsuccinate --> AMP |
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3) IMP
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IMP dehydrogenase
IMP--> XMP NAD + H20 --> NADH + H2O |
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4) IMP
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GMP synthetase
XMP-->GMP glutimate + ATP -->glutimine + AMP + PPi |
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5) IMP
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AMP deaminase
H20 --> NH4 adenosine deaminase H20 --> NH4 |
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6) IMP
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GMP reductase
NADPH --> NADP |
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regulation AMP deaminase
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negative : GDP, GTP, Pi
positive: ATP, K+ |
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regulaton of GMP reductase
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negative: XMP
positive; GTP |
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7) IMP
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nucleosidase
H2O--> Pi |
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8) IMP
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Purine nucleotide phosphorylase
Pi --> ribose 1- phosphate produces base |
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9) IMP
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guanine deaminase
H20 --> NH4 |
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10) IMP
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Xanthine oxidase
O2 + H2O --> H202 |
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competitive inhibitors
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11) HGPRT
12) APRT |
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11) IMP
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Hydroxythanine + PrPP --> IMP + PPi
Guanine + PRPP --> GMP + PPi IMP and GMP competive inhibitors |
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12) IMP
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Adenine phosphoribosyl transferase
Adenine + PRPP --> AMP + PPi AMP competitive inhibitor |
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Deficiencies in purine synthesis
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#1 Purine Nucleotide Phosphorylase Deficiency
in enzyme 8 #2 severe combined Immunodeficinecy (SCID) in enzyme 5 #3 Lesch-Nylan Syndrome in enzyme 11 #4 primary gout in Purine pathway enzyme 1 #5 Von Gierkes disease #6 Xanthurnia |
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Defiency #1
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Purine nucleotide deficiency in enzyme number 8 (lack)
leads in increase in purine nucleotides decrease uric acid formation impaired T-cell function less severe than SCID |
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Deficiency #2
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Severe combined immunodeficiency SCID
enyzme: adenosine deaminase (8) lack of enzyme leads to both T-Cell and B-cell dysfunction early-dealth overwhelming infection gene therary treatment |
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Deficiency #3
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Lesch-Nylan Syndrome
also caused by Gout (deficiency) enzyme deficiency in HGPRT (11) (lack of HGPRT functional gene) X-linked increase purine synthesis neuroproblems hyperuricemia decrease IMP/GMP increases PRPP allipurnol |
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allipurnol
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decreases deposition sodium urate crystals
becomes oxidized to form alloxanthine which is a negative inhibitor of xanthine oxidase thus decrease uric formation |
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Defiency #4
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Secondary gout
enzyme Purine 1: PRPP synthetase (increased activity) causes hyperuricemia overproduction of purine nucleotides sodium urate crystals |
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Hydroxyurea
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decreased nucleoside disphosphate reductase
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regulation of Glutamine-PrPP amidotransferase
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allosterically
inhibited: ATP, ADP, AMP inhibited: GTP, GDP, GMP stimulated: PRPP |
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what happens when ADA is gone
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SCID
deoxyadenosine is usually phosphorylated to form dATP 50 fold amounts in lympocytes that contain alot of salvaging exzyme dATP inhibits ribonucleotide synthetase, preventing dNTP overall effect is the inhibition of DNA synthesis of the lympocytes horrible infections |
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clinical manefestation of Lesch-Nyhan
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severe symptoms of gout
severe malfunction of neurosystem because hyperuricemia (NH4+ is neurotoxic) self-mutilation death before 20th year |
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Defiency #5
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Von Gierkes
Glucose 6 Phosphotatase GNG enzyme #4 increase availibility of substrate (glucose 6-phosphate) increases flux through HMP increased ribose 5-phosphate increased PRPP increased purines increased uric acid |
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Deficiency #6
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xanthinuria
enzyme: xanthine oxdiase 10 lack clinical: hyperuricemia, xanthine renal lithiasis |
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RRPP is used for
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1) synthesis of purines
2) synthesis of pyrimidines 3) synthesis of NAD 4) salvage of nucleotide bases |
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step 1 purines is inhibited by
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dinucleotides
ADP 2,3-bisphosphoglycerate |
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step 1 purines is stimulated by
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inorganic phosphate
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where did ribose-5-phosphate come from
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Hexose monophosphate shunt
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three phases of purine synthesis
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1) formation of IMP
2) conversion of IMP to GMP 3) conversion of IMP to AMP |
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regulation of step 2 purines
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PRPP amidotransferase
activated by PRPP inhibited by AMP, GMP, IMP |
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number of steps between 2 and 11
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9 steps
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name the purine bases
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adenine and guanine
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name the pyrimidine bases
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cytosine
uracil thymine |
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name the purine nucleoside
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base-ribose
adenosine guanosine |
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name the purine nucleotides
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AMP, GMP
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what is the nucleotide with the highest concentration
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ATP
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what is the order of nucleotide, nucleoside, and base prevalane
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1) nucleotide
2) nucleoside 3) base |
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regulation of purine 6
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GMP reductase
inhibition: XMP activation: GTP |
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regulation of purine 5
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GDP, GTP, P inhibition
ATP, K activation |
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regulation of purine 3
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inhibition GMP
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regulation of purine 1
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inhibition: AMP
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GTP stimulates
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IMP and AMP
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ATP stimulates
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IMP, GMP
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purine enzyme 9 is also called
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guanase
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regulation of HGPRTase
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GMP, IMP (inhibited)
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regulation of ARPTases
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inhibited by AMP
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sources of nucleotides
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1) Amino acids
2) Formate 3) CO2 4) PRPP |
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purine nucleotide cycle
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1) AMP --> IMP
2) IMP--> Adenylosuccinate 3) Adenylosuccinate-->AMP step 3 gives off a fumerate on the TCA cycle, to regenerate the muscle cells own source of energy |
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urinary end product of purines
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uric acid
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