EN
Prolyl iminopeptidase from sunflower seed (Helianthus annuus L.) was purified to molecular homogeneity. It is a 105-kDa heterodimer consisting of two subunits: 53 and 55 kDa. It has pI of 6.2 and optimal activity at pH 8.0–8.5 and 45–50℃. The inhibitory analysis was inconclusive about its catalytic machinery, as a significant degree of modification was not observed with any of the used diagnostic inhibitors. Its specificity is restricted to removal of N-terminal prolyl residues.