Adenylate kinase isoenzyme 5

Adenylate kinase isoenzyme 5 (AK5) is a nucleoside monophosphate kinase that catalyzes reversible phosphate transfer between nucleoside triphosphates and monophosphates, with activity on AMP, dAMP, and broader nucleoside diphosphate kinase capacity (UniProt: Q9Y6K8). The protein functions in cellular energy metabolism and nucleotide homeostasis across multiple tissues.

AK5 has been identified in Alzheimer's Disease proteomics studies but shows no specific disease annotation in UniProt. Analysis of post-mortem AD brain tissue versus age-matched controls using TMT-labeled quantitative proteomics across four subcellular fractions (P2, P3, S2, S3) revealed an ambiguous regulation pattern, with a mean log2 fold-change of 0.69 (Chaparral AD proteomics). The ambiguous direction suggests differential regulation across subcellular compartments or inconsistent changes between biological replicates, warranting further investigation to clarify AK5's role in AD pathology.