Two adrenal opioid polypeptides: proposed intermediates in the processing of proenkephalin.

Abstract

Two enkephalin-containing polypeptides of 3600 and 4900 daltons have been isolated from extracts of bovine adrenal medulla, purified to homogeneity, and analyzed by a combination of automated Edman degradation and enzymatic time course hydrolysis. The 4900-dalton polypeptide contains two copies of enkephalin, one an internal [Metlenkephalin sequence, the other a [Leu]enkephalin sequence at the carboxyl terminus. Sequence analysis of the 3600-dalton polypeptide has not been completed, but the polypeptide has been shown to contain a single Met enkephalin sequence followed by an -Arg-Phe linkage that forms the carboxyl terminus of the molecule. On the basis of these and other findings, we propose that the above enkephalin-containig polypeptides are intermediates in the biosynthesis of the enkephalins and that they are generated by posttranslational processing from a large multivalent enkephalin precursor molecule, proenkephalin. The term "multivalent' is used to indicate a polypeptide with many identical functional sequences.

Co-localization and characterization of immunoreactive peptides derived from two opioid precursors in guinea pig adrenal glands

“…The Journal of Neuroscience Guinea Pig Adrenal-Co-localization of Two Opioid Precursors 3427 enkephalin-Arg-Phe and Met-enkephalin-Arg-Gly-Leu assays recognized material of high molecular weight which would be comparable with the previously characterized 3.6-kilodalton (Stern et al, 1981) and 5.3-kilodalton species found in bovine adrenal (Jones et al, 1982). With regard to the prodynorphin markers, the major o(-neoendorphin-immunoreactive peak eluted at the position of '%-neoendorphin.…”

Peptide Mapping Studies of the Chromogranins and of Two Chromaffin Granule Proteoglycans

“…Thus, although the chromogranins represent a family of acidic glycoproteins that have similar amino acid compositions (Smith and Kirshner, 1967;Strieder e t al., 1968;Helle and Serck-Hanssen, 1969) and isoelectric points (Baumgartner et al, 1974) and that are immunochemically crossreactive , a number of the tryptic peptides obtained are not common to all of the fractions studied here. It is likely that many of the chromogranins are formed in vivo by endogenous proteases present within the chromaffin granules, as is known to occur in the case of several opioid peptides (Kilpatrick et al, 1981 ;Stern et al, 1981). (We can assume that these enkephalin- containing polypeptides are also present as minor components of our fractions containing the smaller chromogranins.)…”

Molecular forms of the putative enkephalin precursor BAM-12P in bovine adrenal, pituitary, and hypothalamus.

“…The presence of BAM-12P-like immunoreactivity in the bovine hypothalamus suggests that the same multivalent proenkephalin originally isolated from the adrenal medulla (2)(3)(4)(5) exists in the central nervous system. Indeed, Lewis et al.…”

“…Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile-Arg-Pro-Lys-LeuLys-OH (dynorphin [1][2][3][4][5][6][7][8][9][10][11][12][13] <0 other extracts, however, a dose-dependent and parallel displacement of the BAM-12P tracer was observed. Using these curves we estimated that there is 1.5 ug of BAM-12P-like immunoreactivity in one gland-equivalent of adrenal medulla, 12 ng in one gland-equivalent ofadrenal cortex, 10 ng in one glandequivalent of neurointermediate pituitary, and 2 ng in the hypothalamus.…”

“…The detection of enkephalin immunoreactivity in the adrenal medulla has led to the isolation of several enkephalin-related peptides (1)(2)(3)(4). Lewis et al (5) have shown that a high molecular weight precursor molecule contains several copies of the pentapeptides [Met]-and [Leu]enkephalin.…”