Presence of a membrane bound pyroglutamyl amino peptidase degrading thyrotropin releasing hormone in rat brain.

摘要: In the present work we studied pattern of degradation [3H-Pro]-TRH by soluble and membrane fractions from rat brain. Demonstration bound or nature activities was obtained comparing their distribution to that lactate dehydrogenase looking at effect NaCl washes on fractions. We observed pyroglutamyl amino peptidase activity detected in brain homogenates is a result two different enzymes. One them enzyme previously characterized, needs DTT EDTA for its expression, inhibited SH-blocking agents such as iodoacetamide utilizes p-glu-beta-naphtylamide substrate. The other one, enzyme, chelating DTT, not affected does degrade p-glu-beta-naphtylamide. later presents some specificity towards TRH shown competition experiments with analogs. were able corroborate post proline cleaving acting enzyme. membranes demonstrated also presence post-proline dipeptidyl aminopeptidase. pyroglutamidase potential new source L-his-L-pro-diketopiperazine degrading particular importance searching an inactivation mechanism this peptide once it released into synaptic cleft.