NITROXIDES FOR USE AS CONTRAST AGENTS FOR OVERHAUSER MAGNETIC RESONANCE IMAGING (OMRI)

摘要

The present invention relates to an in vitro method for detecting and/ or quantifying the catalytic activity of an enzyme E, said method comprising the steps of: i) Contacting enzyme E with a compound of formula (la), or (lb): ii) Monitoring the conversion of compound (la) or (lb) into compound (IlIa) or (lllb) by Electron Paramagnetic Resonance (EPR) or Overhauser-enhanced Magnetic Resonance Imaging (OMRI), or by Proton Electron Double Resonance Imaging (PEDRI) thereby detecting or quantifying the activity of enzyme E wherein: Y is OC(=O), S(C=O), NR7; X is CH or N; R1, R2, R3, are each independently selected from C1-C6 alkyl optionally substituted by OH, NRe, COOH; R4, R5 are each independently selected from H, C1-C6 alkyl, C1-C6 alkoxy, NR8R9, SR10;R6 is H or C1-C6 alkyl; ==W is =W or is absent; W is O, S, or NR11; R7, R8, R9, R10, R11 are each independently selected from C1-C6 alkyl; n is 0, 1, 2 or 3, Z is a substrate residue of an enzyme E.