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Adenosine : a purine
nucleoside composed of adenine linked by its N9 nitrogen to the C1 carbon
of ribose. It is a component of ribonucleic acid and its nucleotides
(AMP., ADP, ATP, cAMP) play important roles in biochemical processes such
as synthesis of nucleic acids and proteins, photosynthesis, muscle
contraction and intracellular signal transduction (cAMP). AMP., ADP, ATP
are three interconvertible compounds in which adenosine is attached
through its ribose group to one (monophosphate), two (diphosphate), and
three (triphosphate) phosphoric acid molecules.
Adenosine Triphosphate
(ATP) : a nucleotide composed of adenine, the sugar ribose, and three
phosphate groups; involved in energy metabolism and required for RNA
synthesis. It exists in cells in a form of high-energy phosphate bond to
store and transport chemical energy. The pyrophosphate nature of the
bonds between ATP's three phosphate radicals results in a powerful donor
of phosphate groups to suitable acceptors. When it is broken down by
hydrolysis, it yields ADP (adenosine diphosphate), inorganic phosphorus,
and energy. The free energy derived from hydrolysis of ATP is used to
drive metabolic reactions including the synthesis of nucleic acids and
proteins, to move molecules against concentration gradients (active
transport), and to produce mechanical motion (contraction of microfibrils
and microtubules). ADP can be further broken down to yield adenosine
monophosphate (AMP), additional phosphorus, and more energy. When the
phosphorus and energy are immediately used to drive other reactions, such
as the synthesis of UDP (uridine diphosphate), an RNA precursor, from UMP
(uridine monophosphate), the pair of reactions are said to be coupled.
New ATP is produced from AMP using the energy released from the breakdown
of fuel molecules, such as fat and glucose which is broken down into pyruvate
in the cytosol. Two molecules of ATP are generated for each molecule of
glucose. ADT can be converted back to ATP by the processes of oxidative
phosphorylation and substrate-level phosphorylation.
Adenosine Diphosphate
(ADP) : a nucleotide composed of pyrophosphate of adenosine, involved in
energy metabolism; it is produced by hydrolysis of ATP and converted back
to ATP by the processes of oxidative phosphorylation and substrate-level
phosphorylation.
Adenosine
Monophosphate (AMP, also called adenylic acid.) : a nucleotide,
5'-phosphate of adenosine, produced by the hydrolysis of ATP and
converted to ADP by adenylate kinase. Involved in the reactions of
intracellular energy transfers.
Cyclic Adenosine
Monophosphate (cAMP) : cyclic AMP containing an additional ester linkage
between the phosphate and ribose units; serves as an intracellular and,
in some cases, extracellular secondary messenger mediating the action of
many peptide or amine hormones. It also plays a role in the transcription
of some genes.
Deoxyadenosine (dA) :
a purine nucleoside composed of adenine linked by its N9 nitrogen to the
C1 carbon of deoxyribose. (deoxy-, also called desoxy, is a prefix for
the designation of compounds which contain one less atom of oxygen than
the reference substance).
Deoxyadenosine
diphosphate (dADP) : a nucleotide, 5'-pyrophosphate of deoxyadenosine.
Deoxyadenosine
monophosphate (dAMP) : a nucleotide, 5'-phosphate of deoxyadenosine,
occurring in deoxyribonucleic acid.
Deoxyadenosine triphosphate
(dATP): a nucleotide, the 5’-triphosphate of deoxyadenosine; activated
precursor in DNA synthesis.
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