The present invention refers to the chemical synthesis and potentiality for application in several biochemical assays, of a new alpha -melanocyte stimulating hormone ( alpha -MSH) analogue, labeled with an amino acid-type paramagnetic spin probe (Toac, or 2, 2, 6, 6-tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid). The referred analogue of the present invention, acetyl-Toac<0>- alpha -MSH or briefly EPM-2 are the first publish in the scientific literature which although containing a non-natural compound in its structure, maintained entirely the alpha -MSH activity. Its integral activity associated with the presence of the Toac residue which allow its conformational study through the electron paramagnetic resonance (RPE) spectroscopy associated with the fact that it contains a natural fluorescence (due to the Trp residue of its sequence) give to this labeled analogue a unique potential for a great variety of studies regarding relevant physiological roles already known of this neuroimmunomodulator.
SYNTHESIS OF THE FIRST PARAMAGNETIC AND ACTIVE ANALOGUE (EPM-2) OF THE MELANOCYTE STIMULATING HORMONE CONTAINING AMINO ACID-TYPE STABLE FREE RADICAL