Proline-specific proteases in cultivated neuronal and glial cells.

The activities of several proline-specific endo- and exopeptidases were determined in homogenates of immunocytochemically defined cultures of astrocytes, oligodendrocytes and neurones obtained from rat cerebral cortex. Astrocytes are significantly enriched in post-proline cleaving dipeptidyl peptidase II, prolidase and aminopeptidase P activities; neurones and astrocytes contain prolyl endopeptidase. Dipeptidyl peptidase IV and prolyl carboxypeptidase activities are low or absent in the cultures. The physiological significance of these findings is discussed.