Subcellular ontogeny of brain pyroglutamyl peptidase I.

Abstract The present work studies pyroglutamyl-peptidase I activity in several subcellular fractions of the developing brain. In the synaptosomal fraction, soluble pGlu-peptidase I activity is low until postnatal Day 9 (with a peak at postnatal Day 2) and the activity increases at postnatal Day 15. In later stages there are not significant changes of synaptosomal pGlu-peptidase I activity. However, in the cytosolic fraction the activity is high from ED22 until postnatal Day 9, and afterwards decreases. The changes in the particulate fractions are generally less drastic.