Enzyme inhibition can be determined with PET in similar manner as receptor occupancy.
Enzyme activity parameters are estimated from two PET studies, in baseline, and during medication. Enzyme inhibition (EI) can then be calculated from equation
Useful parameters for calculation of enzyme inhibition are k3 and λk3.
Cumming P, Vasdev N. The assay of enzyme activity by positron emission tomography. Neuromethods 2012; 71: 111-135.
Holland JP, Cumming P, Vasdev N. PET radiopharmaceuticals for probing enzymes in the brain. Am J Nucl Med Mol Imaging 2013; 3(3): 194-216.
Ota T, Shinotoh H, Fukushi K, Kikuchi T, Sato K, Tanaka N, Shimada H, Hirano S, Miyoshi M, Arai H, Suhara T, Irie T. Estimation of plasma IC50 of donepezil for cerebral acetylcholinesterase inhibition in patients with Alzheimer disease using positron emission tomography. Clin Neuropharm. 2010; 33: 74-78.
Updated at: 2015-08-03
Created at: 2011-11-21
Written by: Vesa Oikonen