Beta-Endophin

Cathepsin D (EC 3.4.3.23) purified from human putuitary by affinity chromatography on pepstatin-Sepharose cleaved human beta-endorphin (LPH 61-91) at the Leu(77)-Phe(78) bond after incubation at pH 3.2 for 1-3. Incubation with smaller lipotropic fragments (enkephalin, alpha-endorphin, gamma-endorphin) did not lead to further degradation. Cleavage sites were identified following the separation of danyslated or iodinated peptides on polyamide sheets accompanied by N-group determination, or following slab-gel electrophoresis of the iodinated peptides...

Basal and stimulated secretion of immunoreactive ACTH, LPH and beta-endorphin from four human pituitary tumours has been studied in vitro using a superfused, isolated cell system. Chromatography of cell secretions under acid-dissociating conditions demonstrated that the human tumor cells released immunoreactive peptides with the elution profiles of alpha h (1-39) ACTH, beta h-LPH, gamma h-LPH and beta h-endorphin confirming that beta h-endorphin is secreted by human pituitary tumour cells and is not formed by enzymic cleavage from beta h-LPH in blood...

The isolation and primary structure of two peptides with morphinomimetic activity, obtained from an extract of porcine hypothalamus-neurohypophysis, are described. The amino acid sequence of the two peptides, named alpha-endorphin and gamma-endophin, was determined by mass spectrometry and danxyl-Edman methods to be H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-OH and H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-OH, respectively. These correspond to the amino acid sequences present between residues 61 and 76 and residues 61 and 77 of the various beta-lipotropins...