Purification and amino acid sequence of melanocyte-stimulating hormone from the dogfish Squalus acanthias.
TL;DR: The sequence of the melanocyte-stimulating hormone, Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Met, shows that ten of its 11 residues are the same as ten of the 13 residues of mammalian alpha-MSH.
Abstract: A melanocyte-stimulating hormone (MSH) was isolated by gel filtration and ion-exchange chromatography from extracts of the pituitary glands of dogfish. Sequence studies were carried out on the hormone and its enzymically and chemically cleaved fragments. The sequence of the hormone, Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Met, shows that ten of its 11 residues are the same as ten of the 13 residues of mammalian α-MSH. About half of its molecules have the carboxyl group at the C-terminus free and about half are amidated; about a fifth have an extra tyrosine residue on the N-terminus, thereby making 11 residues the same as in mammalian α-MSH. Unlike the mammalian hormone, however, none of it was found to be N-acetylated.
Citations
More filters
TL;DR: The anatomy, physiology and biochemistry of opiomelanotropinergic neurons are reviewed and the implications of multi-neurotransmitter and multi-hormone neurons and cells are discussed.
540 citations
118 citations
TL;DR: The proopiomelanocortin (POMC) gene was most likely derived from an ancestral opioid‐coding gene following the 1R chordate genome duplication event and a C‐terminally extended opioid sequence (β‐endorphin) was gained.
Abstract: The proopiomelanocortin (POMC) gene was most likely derived from an ancestral opioid-coding gene following the 1R chordate genome duplication event. During the radiation of the jawless fish, the POMC organization plan emerged multiple melanocortin sequences (α-MSH/ACTH and β-MSH) and a C-terminally extended opioid sequence (β-endorphin). Following the 2R genome duplication event, the γ-MSH sequence was gained. Among the jawed vertebrates, three distinct trends in the evolution of the POMC gene are apparent: the gain of the δ-MSH sequence (cartilaginous fish), the loss of the γ-MSH sequence (ray-finned fish), and the retention of the post 2R POMC organization plan (lobe-finned fish/tetrapods). POMC is synthesized in the pituitary gland and in neurons of the hypothalamus, where an array of posttranslational processing mechanisms, such as endoproteolytic cleavage and N-acetylation, generate distinct sets of end-products in these tissues. A striking feature of the melanocortin end-products is the rigorous conservation of the primary sequence of α-MSH and the first 25 amino acids of ACTH.
113 citations
TL;DR: ACTH and β-LPH appear to be synthesised in both the pars distalis and the pars intermedia, and in the Pars distalis they are secreted intact.
102 citations
TL;DR: N-acetylation of alpha-MSH may be an effective regulatory process for modulating the behavioral potency of the secretory product ofalpha- MSH-containing pituitary cells and neurons.
102 citations