NEOKYOTORPHIN FORMATION AND QUANTITATIVE EVOLUTION FOLLOWING HUMAN HEMOGLOBIN HYDROLYSIS WITH CATHEPSIN-D

In vitro human hemoglobin hydrolysis by cathepsin D was investigated. The quantitative evolution of neokyotorphin following the hydrolysis w as determined by high-performance liquid chromatography coupled with a photodiode array detector. Spectral comparisons allowed us to identif y neokyotorphin in the hydrolysates all along the hydrolysis. Second o rder derivative spectrometry was used in order to verify the presence of tyrosine in the peptide. This provided informations about the mecha nism of cathepsin D activity towards hemoglobin. Moreover it confirmed that hemoglobin could appear as a precursor of some bioactive peptide s following proteolytic degradation. (C) 1998 Elsevier Science Inc.