Proteolysis of beta-endorphin in brain tissue.

The processing of beta-endorphin by brain enzymes into peptides related to the behaviorally active gamma- and alpha-type endorphins and the sequence of proteolytic events in the conversion process are described. Multiple enzyme activities contribute to the generation of the peptides with neurotropic activity. It is proposed that the processing into gamma- and alpha-type neuropeptides is a post-secretional event. The enzymes involved may have a key role in the nature and levels of neurotropic beta-endorphin fragments in the brain.