Internally, adenosine is transformed into inosine and S-(5′-Adenosyl)-L-homocysteine (AdoHcy) by adenosine deaminase (ADA) and S-adenosyl-L-homocysteine hydrolase (SAHH) respectively. Additionally, adenosine #kinase helps to maintain the concentration of adenine #nucleosides/#nucleotides by converting adenosine into adenosine monophosphate. Finally, during cellular injury or hypoxia/#ischemia, adenosine is formed from #ATP and is transported inside the #cell using #transmembrane proteins.