How is ATP converted to adenosine? I am familiar with adenosine diphosphate (ADP) and adenosine triphosphate (ATP), how one relates to the other, and how each is formed in cellular respiration and photosynthesis, but I am confused as to how regular adenosine is formed. I was reading an article on caffeine which stated: > Caffeine is structurally similar to adenosine, a neuromodulator, whose formation is dependent on the relative rates of ATP breakdown and synthesis. From this I concluded that ATP can be changed to regular adenosine, and adenosine back to ATP, but I cannot find anything else on the internet to support my conclusion. I was also wondering _when_ and _why_ your body would change ADP into adenosine instead of ATP. I assume that AMP plays a role in all of this, and possibly ADA. I only have a high school level education in biology, so please bear with me. If you do not mind, please include a source in your answer so I can further research on my own. Thanks!

For a full understanding I refer you to the KEGG pathway map which is fairly comprehensive in showing all the metabolic processes that CAN produce Adenosine. It's a bit daunting but if you find it on the map here it is interactive and you can see the enzymes and pathways involved. If you drill down it brings you to a host of papers and references in primary literature to back things up.

However the dominant process is as follows:


2 ADP <=> ATP + AMP


enacted by an adenylate kinase then:


AMP + H2O <=> Adenosine + phosphate


enacted by adenosine 5'-monophosphate phosphohydrolase (a 5'-Nucleotidases )