An NMR study of the interaction between melanin free acid and Mn2+ ions as a model to mimic the enhanced proton relaxation rates in melanotic melanoma.
The interaction of a soluble Melanin Free Acid (MFA) from Sepia melanin with Mn2+ ions is investigated by measuring the proton water relaxation rates. The similarity between MFA and the parent melanin is assessed by means of their high resolution 13C cross polarization magic angle spinning NMR spectra. The observed marked increase in longitudinal proton relaxation rates and the characteristic 1/T1 NMRD profile are associated to the formation of a macromolecular metal complex. The presence of similar paramagnetic species is expected to cause the high contrast shown by melanotic tissues in MRI.
Aime
S
S
Dipartimento di Chimica Inorganica, Università degli Studi di Torino, Italy.
Fasano
M
M
Terreno
E
E
Sarzanini
C
C
Mentasti
E
E
D000818:Animals; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008345:Manganese; D008543:Melanins; D008545:Melanoma / Q000175:diagnosis*
D008543:Melanins; D008345:Manganese