A condensation product of adenosine and phosphoric acid; a nucleotide found among the hydrolysis products of all nucleic acids. 3′-Adenylic acid (adenosine 3′-monophosphate) and 5′-adenylic acid [adenosine 5′-monophosphate (AMP)] differ in the place of attachment of the phosphoric acid to the d-ribose; deoxyadenylic acid differs in having H instead of OH at the 2′ position of d-ribose.AMP. SYN: adenine nucleotide.