ENZYMES IN MEDICINE
ENZYMES IN CLINICAL DIAGNOSIS
secretory - produced by tissues (namely liver), acting in plasma – prothrombin, plasminogen, cerruloplasmin, choline esterase; lipoprotein lipaseEnzymes intracellular – function intracellulary, have no physiological use in plasma - membrane bound – ALP, GMT - cytosolic – ALT, AST, LD, MDH - mitochondrial – AST, GMDH - lysosomal - ACP - tissue specific – glucose-6-phosphatase – liver amylase – pancrease LD1 – heart
Examples of isoenzymes and enzymes commonly assayed for diagnostic purposes
Enzyme Location Cause of elevated plasma levelAcid phosphatase - ACP Prostate Prostatic cancerAlkaline phosphatase – ALP Bone, liver Rickets, hypoparathyroidism, osteomalacia, obstructive jaundice, cancer of bone/liverAlanine aminotransferase – ALT Liver (muscle, Hepatitis, jaundice, circulatory heart, kidney) faillure with liver congestionAspartate aminotransferase – AST Heart, muscle, Myocardial infarction, muscle red cells, liver damage, anemia, hepatitis, circulatory faillure with liver congestionAmylase - AM Pancras Acute pancreatitis, peptic ulcer-Glutamyl transferase – GMT Liver, kidney, Hepatitis, alcoholic liver pancreas damage, cholestasis
Examples of isoenzymes commonly assayed for diagnostic purposes
Enzyme Location Cause of elevated plasma levelCreatine kinase – CKCK-MB Heart Myocardial infarctionCK-MM Skeletal muscle Muscular dystrophyLactate dehydrogenase – LDLD1 > LD2 Heart, kidney, Myocardial infarction, kidney blood cells disease, megaloblastic anemia, leukemiaLD2, LD3 LeukemiaLD5 Liver, muscle Liver disease, muscle damage
