The possibility of participation of different protein kinases in the regulation of degradation of Glp6[125I]Tyr8SP6-11 with different endopeptidases in subcellular fractions of rat brain.

1. Nuclear fraction of cortex and synaptosomal fraction of hippocampus of rat brain were preincubated with ATP and different, "second messengers" as well as some "classical" neurotransmitters and then incubated with Glp6[125I]Tyr8SP6-11 (JP). 2. It was found that different neurotransmitters and especially "second messengers" might be involved in the activation or inhibition of peptidase I and II. 3. Activation of different protein kinases results in substantial modulation of degradation of JP (SP C-terminal fragment). 4. The data confirm that products of one peptidase might be inhibitors of the second peptidase acting on JP, although the second enzyme might be affected additionally in conditions activating different protein kinase systems.