Adenosine diphosphate
Names | |
---|---|
IUPAC name
Adenosine 5′-(trihydrogen diphosphate)
| |
Systematic IUPAC name
[(2R,3S,4R,5R)-5-(6-Amino-9H-purin-9-yl)-3,4-dihydroxyoxolan-2-yl]methyl trihydrogen diphosphate | |
Other names
Adenosine 5′-diphosphate; Adenosine 5′-pyrophosphate; Adenosine pyrophosphate
| |
Identifiers | |
3D model (
JSmol ) |
|
ChEBI | |
ChEMBL | |
ChemSpider | |
DrugBank | |
ECHA InfoCard
|
100.000.356 |
EC Number |
|
IUPHAR/BPS |
|
KEGG | |
PubChem CID
|
|
RTECS number
|
|
UNII | |
CompTox Dashboard (EPA)
|
|
| |
| |
Properties | |
C10H15N5O10P2 | |
Molar mass | 427.201 g/mol |
Density | 2.49 g/mL |
log P | -2.640 |
Hazards | |
Safety data sheet (SDS) | MSDS |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|
Adenosine diphosphate (ADP), also known as adenosine pyrophosphate (APP), is an important
ADP can be interconverted to adenosine triphosphate (ATP) and adenosine monophosphate (AMP). ATP contains one more phosphate group than does ADP. AMP contains one fewer phosphate group. Energy transfer used by all living things is a result of dephosphorylation of ATP by enzymes known as ATPases. The cleavage of a phosphate group from ATP results in the coupling of energy to metabolic reactions and a by-product of ADP.[1] ATP is continually reformed from lower-energy species ADP and AMP. The biosynthesis of ATP is achieved throughout processes such as substrate-level phosphorylation, oxidative phosphorylation, and photophosphorylation, all of which facilitate the addition of a phosphate group to ADP.
Bioenergetics
ADP cycling supplies the
It takes multiple reactions between myosin and actin to effectively produce one muscle contraction, and, therefore, the availability of large amounts of ATP is required to produce each muscle contraction. For this reason, biological processes have evolved to produce efficient ways to replenish the potential energy of ATP from ADP.[2]
Breaking one of ATP's phosphorus bonds generates approximately 30.5
Cellular respiration
Catabolism
The ten-step
Glycolysis
Glycolysis is performed by all living organisms and consists of 10 steps. The net reaction for the overall process of glycolysis is:[6]
- Glucose + 2 NAD+ + 2 Pi + 2 ADP → 2 pyruvate + 2 ATP + 2 NADH + 2 H2O
Steps 1 and 3 require the input of energy derived from the hydrolysis of ATP to ADP and Pi (inorganic phosphate), whereas steps 7 and 10 require the input of ADP, each yielding ATP.[7] The enzymes necessary to break down glucose are found in the cytoplasm, the viscous fluid that fills living cells, where the glycolytic reactions take place.[1]
Citric acid cycle
The citric acid cycle, also known as the Krebs cycle or the TCA (tricarboxylic acid) cycle is an 8-step process that takes the pyruvate generated by glycolysis and generates 4 NADH, FADH2, and GTP, which is further converted to ATP.[8] It is only in step 5, where GTP is generated, by succinyl-CoA synthetase, and then converted to ATP, that ADP is used (GTP + ADP → GDP + ATP).[9]
Oxidative phosphorylation
Oxidative phosphorylation produces 26 of the 30 equivalents of ATP generated in cellular respiration by transferring electrons from NADH or FADH2 to O2 through electron carriers.[10] The energy released when electrons are passed from higher-energy NADH or FADH2 to the lower-energy O2 is required to phosphorylate ADP and once again generate ATP.[11] It is this energy coupling and phosphorylation of ADP to ATP that gives the electron transport chain the name oxidative phosphorylation.[1]
Mitochondrial ATP synthase complex
During the initial phases of
Blood platelet activation
Under normal conditions, small disk-shape platelets circulate in the blood freely and without interaction with one another. ADP is stored in dense bodies inside blood platelets and is released upon platelet activation. ADP interacts with a family of ADP receptors found on platelets (P2Y1, P2Y12, and P2X1), which leads to platelet activation.[14]
- P2Y1 receptors initiate platelet aggregation and shape change as a result of interactions with ADP.
- P2Y12 receptors further amplify the response to ADP and draw forth the completion of aggregation.
ADP in the blood is converted to
See also
References
- ^ ISBN 978-0-7167-7108-1.
- ^ a b c Nave, C.R. (2005). "Adenosine Triphosphate". Hyper Physics [serial on the Internet]. Georgia State University.
- ^ a b Farabee, M.J. (2002). "The Nature of ATP". ATP and Biological Energy [serial on the Internet]. Archived from the original on 2007-12-01.
- PMID 22199166.
- PMID 17071828.
- ^ Medh, J.D. "Glycolysis" (PDF). CSUN.Edu. Archived (PDF) from the original on 2022-10-09. Retrieved 3 April 2013.
- ^ Bailey, Regina. "10 Steps of Glycolysis". Archived from the original on 2013-05-15. Retrieved 2013-05-10.
- ^ "Citric Acid Cycle" (PDF). Takusagawa’s Note. Archived from the original (PDF) on 24 March 2012. Retrieved 4 April 2013.
- ^ "Biochemistry" (PDF). UCCS.edu. Archived from the original (PDF) on 2013-02-28.
- ^ "Oxidative phosphorylation". W H Freeman, 2002. Retrieved 4 April 2013.
- ^ Medh, J. D. "Electron Transport Chain (Overview)" (PDF). CSUN.edu. Archived (PDF) from the original on 2022-10-09. Retrieved 4 April 2013.
- PMID 17161604.
- ISBN 0-07-121766-5.
- PMID 16368572.