[Elimination and excretion of adenylate kinases following cell damage]

Adenylate kinases, small organ-specific isoenzymes which appear after tissue damage in the blood plasma are partly eliminated via the kidney. After intravenous administration of 3000 enzyme units of 14C-labelled adenylate kinase to rats, about 50% of the enzyme and of the radioactivity are found in the urine within 7 minutes. The elimination of adenylate kinase from the serum occurs in two phases, a faster (half-life 16 minutes) and a slower (half-life 160 minutes). After intravenous adminstration of adenylate kinase to humans, a part of the activity was recovered in the urine within minutes. The potential use of assaying adenylate kinase levels for early diagnosis of myocardial infarction is discussed. Using various skeletal muscle diseases as examples, the possible use of the very rapid elimination of adenylate kinase from the serum in monitoring the course of the acute illnesses is described. The competitive inhibitor diadenosine pentaphosphate (AP5A) has a much higher affinity for the adenylate kinases from erythrocytes, heart or skeletal muscle than for the isoenzymes from liver or kidney. Therefore, AP5A can be used for the differential determination of adenylate kinase isoenzymes in the blood plasma or the urine.