Correcting for incomplete saturation and off-resonance effects in multiple-site saturation-transfer kinetic measurements.
The effects of incomplete saturation and off-resonance irradiation on nuclear magnetic resonance saturation-transfer measurements of three-site chemical-exchange rates are discussed. A new method that uses double-saturation measurements is compared with two published methods, one that uses single-saturation measurements and one that uses a single-saturation measurement and a double-saturation measurement. Several formulas are compared for measuring the exchange rate constant k(DE) for exchange from a detected spin D to an exchanging spin E in the presence of exchange from spin D to a competing spin C. For each method, formulas are derived with corrections for incomplete saturation or off-resonance effects, with both corrections, and with neither correction. Exact formulas are available for three exchanging sites with incomplete saturation if there are no off-resonance effects. Off-resonance corrections are imperfect even with complete saturation.
Kingsley
P B
PB
Department of Radiology, North Shore University Hospital, 300 Community Drive, Manhasset, New York, 11030 USA. kingsley@nshs.edu
Monahan
W G
WG
D000465:Algorithms; D003402:Creatine Kinase / Q000737:chemistry; D004574:Electromagnetic Fields; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D013113:Spin Labels; D009626:Terminology as Topic
D013113:Spin Labels; D003402:Creatine Kinase