# Adenosine monophosphate

**Adenosine monophosphate** (AMP), also called 5'-adenylic acid or adenosine 5'-monophosphate, is a nucleotide consisting of the nucleobase adenine, the pentose sugar ribose, and a single phosphate group esterified to the sugar<sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/AMP)</sup>. It is one of the four nucleotides of RNA, where its residue is written simply as A<sup>[2](https://www.ncbi.nlm.nih.gov/books/NBK21052/)</sup>, and it is a fundamental metabolite produced by all living cells<sup>[3](https://www.ebi.ac.uk/chebi/CHEBI%3A2356)</sup>. Beyond its structural role in RNA, AMP serves as a metabolic signal of cellular energy status, a product and substrate of adenylate kinase, and a precursor or degradation product in purine metabolism<sup>[4](https://www.nature.com/articles/s41580-022-00547-x)</sup>.

| Key fact | Detail |
|---|---|
| Composition | Adenine + ribose + one phosphate group; an ester of phosphoric acid with the nucleoside adenosine<sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/AMP)</sup> |
| Formula and mass | C\(_{10}\)H\(_{14}\)N\(_{5}\)O\(_{7}\)P; average mass 347.224, monoisotopic mass 347.06308<sup>[3](https://www.ebi.ac.uk/chebi/CHEBI%3A2356)</sup> |
| CAS registry number | 61-19-8<sup>[3](https://www.ebi.ac.uk/chebi/CHEBI%3A2356)</sup> |
| Role in RNA | One of the four nucleotides of RNA; the residue is abbreviated A<sup>[2](https://www.ncbi.nlm.nih.gov/books/NBK21052/)</sup> |
| Adenylate kinase reaction | AMP + ATP = 2 ADP (EC 2.7.4.3)<sup>[5](https://enzyme.expasy.org/EC/2.7.4.3)</sup> |
| Signaling role | Rising AMP:ATP and ADP:ATP ratios activate AMP-activated protein kinase (AMPK), the cellular energy sensor<sup>[4](https://www.nature.com/articles/s41580-022-00547-x)</sup> |
| ChEBI roles | Fundamental metabolite, cofactor, adenosine A\(_1\) receptor agonist, inhibitor of alkaline phosphatase and fructose-bisphosphatase<sup>[3](https://www.ebi.ac.uk/chebi/CHEBI%3A2356)</sup> |

## Structure and chemical identity

AMP consists of three parts: the phosphate group, the pentose sugar ribose, and the nucleobase adenine<sup>[1](https://pubchem.ncbi.nlm.nih.gov/compound/AMP)</sup>. In the common 5'-form the phosphate is esterified to the 5'-carbon of the ribose; the broader term adenosine phosphate covers phosphate at the 2'-, 3'-, or 5'-position<sup>[6](https://pubchem.ncbi.nlm.nih.gov/compound/Adenosine-Monophosphate)</sup>. The compound is negatively charged at physiological pH, with reported pK\(_1\) = 6.0 and pK\(_2\) = 9.8 for the phosphate group<sup>[7](https://api.drum.lib.umd.edu/server/api/core/bitstreams/84899121-2c57-42d8-baad-b05ee5d7814b/content)</sup>.

**Relationship to ADP, ATP, and cAMP.** The adenine nucleotides differ only in phosphate count: AMP has one phosphate group, ADP two, and ATP three<sup>[8](https://www.sciencenewstoday.org/atp-adp-and-amp-how-nucleotides-power-cellular-processes)</sup>. The phosphate in AMP is a normal ester link of the low-energy type, whereas ATP and ADP contain phosphoanhydride bonds<sup>[9](https://uomustansiriyah.edu.iq/media/lectures/4/4_2024_05_19%2110_54_04_PM.pdf)</sup>. Cyclic AMP (cAMP) is a distinct molecule in which a single phosphate is esterified to both the 3' and 5' hydroxyl groups of the ribose, forming a cyclic structure; it is derived from ATP and acts as a second messenger in hormone-regulated signaling<sup>[10](https://library.med.utah.edu/NetBiochem/pupyr/pp.htm)</sup><sup> • </sup><sup>[11](https://publications.iupac.org/pac/1973/pdf/3504x0411.pdf)</sup>.

## AMP as an energy signal

When cellular energy status falls, ATP is converted to ADP, and the enzyme adenylate kinase interconverts the adenine nucleotides through the reaction AMP + ATP = 2 ADP<sup>[5](https://enzyme.expasy.org/EC/2.7.4.3)</sup>. Because this reaction maintains AMP at low levels in unstressed cells, a rise in the AMP:ATP ratio is a sensitive indicator of energy stress<sup>[12](https://pmc.ncbi.nlm.nih.gov/articles/PMC3949207/)</sup>. The cellular energy charge, defined as the ratio \( [\mathrm{ATP} + 0.5 \cdot \mathrm{ADP}] / [\mathrm{ATP} + \mathrm{ADP} + \mathrm{AMP}] \), summarizes the charging state of the adenylate pool<sup>[13](https://pmc.ncbi.nlm.nih.gov/articles/PMC6390775/)</sup>.

The main reader of this signal is [AMP-activated protein kinase](https://www.edgepedia.org/amp-activated-protein-kinase) (AMPK). Its classical role is as a cellular energy sensor activated by falling energy status, signaled by increases in the AMP:ATP and ADP:ATP ratios; once activated, AMPK promotes ATP-producing catabolic pathways while inhibiting energy-consuming processes<sup>[4](https://www.nature.com/articles/s41580-022-00547-x)</sup>. The γ-subunit of AMPK binds AMP, ADP, and ATP, which confers the kinase its ability to sense the energy state of the cell<sup>[14](https://pmc.ncbi.nlm.nih.gov/articles/PMC5553560/)</sup>. AMPK also responds to non-canonical signals, including the availability of glucose, glycogen, or fatty acids, and damage to lysosomes and nuclear DNA<sup>[4](https://www.nature.com/articles/s41580-022-00547-x)</sup>.

## Biosynthesis

In de novo purine biosynthesis, the purine ring is assembled directly on ribose-5-phosphate, and the pathway first yields inosine 5'-monophosphate (IMP)<sup>[15](https://www.columbia.edu/cu/biology/courses/w3034/Larry/readings/PurineChapter/PurineChapter.html)</sup>. The branch from IMP to AMP proceeds in two steps: IMP reacts with aspartate and GTP to form adenylosuccinate (releasing GDP and phosphate), and adenylosuccinate lyase then converts adenylosuccinate into AMP and fumarate, with the aspartate amino group becoming the 6-amino group of AMP<sup>[15](https://www.columbia.edu/cu/biology/courses/w3034/Larry/readings/PurineChapter/PurineChapter.html)</sup><sup> • </sup><sup>[16](https://www.amboss.com/us/knowledge/purines-and-pyrimidines)</sup>. AMP and GMP can also be resynthesized from intermediates of the degradation pathway through purine salvage routes<sup>[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC10956446/)</sup>.

## The purine nucleotide cycle

AMP sits at the center of the purine nucleotide cycle, in which AMP is deaminated by [AMP deaminase](https://www.edgepedia.org/amp-deaminase) (AMPD) into IMP, releasing ammonia; IMP and aspartate are then converted into adenylosuccinate by adenylosuccinate synthetase, a reaction requiring GTP hydrolysis to be thermodynamically favorable; and adenylosuccinate lyase closes the cycle by converting adenylosuccinate back into AMP and fumarate<sup>[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC10956446/)</sup>. The fumarate produced feeds the citric acid cycle, boosting its capacity to generate NADH for ATP production<sup>[18](https://pmc.ncbi.nlm.nih.gov/articles/PMC8247561/)</sup>. In muscle, the cycle is described as regulating energy requirements for contraction by maintaining a high ATP:ADP ratio, replenishing citric acid cycle intermediates with fumarate, and supporting amino acid deamination through aspartate formation<sup>[19](https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/purine-nucleotide-cycle)</sup>.

## Degradation

AMP is degraded by two routes: conversion to IMP via AMP deaminase, or dephosphorylation to adenosine via cytosolic 5'-nucleotidases<sup>[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC10956446/)</sup>. Each pathway ends at inosine, which is generated when 5'-nucleotidases act on IMP or when adenosine deaminase acts on adenosine; as inosine is broken down further, the process finally produces uric acid as a waste product.<sup>[17](https://pmc.ncbi.nlm.nih.gov/articles/PMC10956446/)</sup> In plants, the initial step of adenine [nucleotide catabolism](https://www.edgepedia.org/nucleotide-catabolism) is likewise deamination of AMP to IMP by AMP deaminase, followed by dephosphorylation to inosine and hydrolysis to hypoxanthine<sup>[20](https://pmc.ncbi.nlm.nih.gov/articles/PMC3243375/)</sup>.

## Biological and pharmacological roles

ChEBI classifies AMP as a cofactor and a fundamental metabolite, and lists roles as an adenosine A\(_1\) receptor agonist and as an inhibitor of the enzymes alkaline phosphatase (EC 3.1.3.1) and fructose-bisphosphatase (EC 3.1.3.11)<sup>[3](https://www.ebi.ac.uk/chebi/CHEBI%3A2356)</sup>. Nucleotides such as adenosine 5'-monophosphate have been reported to affect immune functions, including enhancement of T-cell maturation and function and of natural killer cell activity<sup>[21](https://pubchem.ncbi.nlm.nih.gov/compound/Adenosine-Phosphate)</sup>.

As a drug, adenosine phosphate was withdrawn by the FDA because it was considered neither safe nor effective for its intended uses as a vasodilator and an anti-inflammatory<sup>[6](https://pubchem.ncbi.nlm.nih.gov/compound/Adenosine-Monophosphate)</sup>.

## References

1. [Adenosine Monophosphate (CID 6083), PubChem](https://pubchem.ncbi.nlm.nih.gov/compound/AMP)
2. [Glossary, Molecular Biology of the Cell, NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK21052/)
3. [adenosine 5'-monophosphate (CHEBI:16027), ChEBI](https://www.ebi.ac.uk/chebi/CHEBI%3A2356)
4. [Steinberg & Hardie (2023). New insights into activation and function of the AMPK. Nature Reviews Molecular Cell Biology 24, 255–272](https://www.nature.com/articles/s41580-022-00547-x)
5. [ENZYME entry EC 2.7.4.3: adenylate kinase, EXPASy](https://enzyme.expasy.org/EC/2.7.4.3)
6. [Adenosine Monophosphate (CID 6083), PubChem](https://pubchem.ncbi.nlm.nih.gov/compound/Adenosine-Monophosphate)
7. [Protonation and charge behavior of AMP in environmental pH conditions, University of Maryland repository](https://api.drum.lib.umd.edu/server/api/core/bitstreams/84899121-2c57-42d8-baad-b05ee5d7814b/content)
8. [ATP, ADP, and AMP: How Nucleotides Power Cellular Processes, Science News Today](https://www.sciencenewstoday.org/atp-adp-and-amp-how-nucleotides-power-cellular-processes)
9. [Lecture notes on high-energy phosphate bonds, Mustansiriyah University](https://uomustansiriyah.edu.iq/media/lectures/4/4_2024_05_19%2110_54_04_PM.pdf)
10. [Purines and Pyrimidines, NetBiochem, University of Utah](https://library.med.utah.edu/NetBiochem/pupyr/pp.htm)
11. [Analogues of cyclic AMP and their biological activity, Pure and Applied Chemistry (IUPAC)](https://publications.iupac.org/pac/1973/pdf/3504x0411.pdf)
12. [AMPK: Regulating Energy Balance at the Cellular and Whole Body Levels, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC3949207/)
13. [Shortage of Cellular ATP as a Cause of Diseases and Strategies to Enhance ATP, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC6390775/)
14. [AMPK: mechanisms of cellular energy sensing and restoration of metabolic balance, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC5553560/)
15. [Purine chapter (Chapter 27), Columbia University course readings](https://www.columbia.edu/cu/biology/courses/w3034/Larry/readings/PurineChapter/PurineChapter.html)
16. [Purines and pyrimidines, AMBOSS knowledge](https://www.amboss.com/us/knowledge/purines-and-pyrimidines)
17. [Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC10956446/)
18. [nucleotide metabolism - pmc](https://pmc.ncbi.nlm.nih.gov/articles/PMC8247561/)
19. [Purine Nucleotide Cycle, ScienceDirect Topics](https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/purine-nucleotide-cycle)
20. [Purine and Pyrimidine Nucleotide Synthesis and Metabolism, PMC](https://pmc.ncbi.nlm.nih.gov/articles/PMC3243375/)
21. [Adenosine Monophosphate (Adenosine-Phosphate), PubChem](https://pubchem.ncbi.nlm.nih.gov/compound/Adenosine-Phosphate)

---
*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Organic substances › Carbonyl and carboxyl chemistry › Carboxylic acid derivatives › Esters › Phosphate, sulfate, and other oxoacid esters › Phosphate esters*

*Initially written Sep 17, 2026 · Reviewed: Oct 15, 2026 · Edited: Oct 15, 2026 · Last review: Oct 15, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license