Download Structure of nucleotides

Classification of nucleotides
• purine nucleotides: contain adenine, guanine,
hypoxanhine or xanthine
• pyrimidine nucleotides: contain cytosine, uracil or
Structure of nucleotides
Vladimíra Kvasnicová
thymine
• ribonucleotides (saccharide = ribose)
• deoxyribonukleotidy (saccharide = deoxyribose)
formed by reduction of ribonucleoside
diphosphates (NADPH)
Structure of purine and pyrimidine
nucleotides
PURINE BASES
• nucleotide = ester of phosphoric acid and a nucleoside
• nucleoside = N-containing base + monosaccharide
• β-N-glycosidic bond between base and saccharide
• nucleotide bases: aromatic heterocycles
purines:
pyrimidine + imidazol ring
pyrimidines:
pyrimidine ring
The figure was adopted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed.
Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
ribonucleoside
deoxyribonucleoside
PYRIMIDINE
BASES
N-glycosidic bond
The figure was adopted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed.
Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
ribonucleosides
The figure was adopted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed.
Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
deoxyribonucleoside
Ribonucleotides
* N-glycosidic bond
* ester bond
* anhydride bond
The figure was adopted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed.
Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
The figure was adopted from Devlin, T. M. (editor): Textbook
of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss,
Inc., New York, 1997. ISBN 0-471-15451-2
ribonucleotide
deoxyribonucleotide
Properties of nucleotides
• strong absorption of UV radiation (260 nm)
• purines are less stable under acidic conditions
than pyrimidines
• polar terminal phosphate groups
alternative names: adenylate or adenylic acid, ...
The figure was adopted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed.
Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
Purine and pyrimidine nucleotides
• essential for all cells
• mainly 5´-nucleosidedi and triphosphates
Nucleotides in a metabolism
1) energetic metabolism
ATP = principal form of chemical energy
available to cells – „as money of the cell“
(30 kJ/mol / spliting off phosphate)
• ribonucleotides: concentration of a sum of them
is constant (mM), only their ratio varies
(main ribonucleotide of cells: ATP)
• deoxyribonucleotides: their concentration
depends on a cell cycle (µM)
phosphotransferase reactions (kinases)
muscle contraction, active transport
2) monomeric units of RNA and DNA
substrates: nucleoside triphosphates
Synthetic analogs of purines and pyrimidines are used
in chemotherapy
3) physiological mediators
cAMP, cGMP
(„second messengers“)
Cyclic adenosine monophosphate
(cAMP)
The figure was adopted from Harper´s Illustrated Biochemistry 26th ed./ R.K.Murray; McGraw-Hill Companies,
2003, ISBN 0-07-138901-6.
4) components of coenzymes
NAD+, NADP+, FAD, CoA
The figure was found at
http://www.benbest.com/health/cycAMP.gif
(Jan 2008)
5) activated intermediates
UDP-Glc, GDP-Man, CMP-NANA
CDP-choline, ethanolamine, diacylglycerol
SAM → methylation
PAPS → sulfatation
6) allosteric efectors
regulation of key enzymes of metabolic pathways
The figures were found at http://lxyang.myweb.uga.edu/bcmb8010/pic/NAD+.gif a
http://oregonstate.edu/instruct/bb450/stryer/ch14/Slide26.jpg (Jan 2008)