Microperoxidase-11 (MP-11) was immobilised at gold electrodes and characterised using UV-vis and resonance Raman spectroscopy. On immersion in a range of non-aqueous solvents, no significant spectroscopic changes were observed. The redox potential of MP-11 was determined in 16 solvents and ranged from -384 to -228 mV. The redox potential was independent of the dielectric constant and hydrophobicity of the solvents examined. (c) 2007 Elsevier Ltd. All rights reserved.