ISOLATION, PURIFICATION, AND CHARACTERIZATION OF Γ-Lipotropic HORMONE FROM SHEEP PITUITARY GLANDS

Chrétien, Michel; Li, Choh Hao

doi:10.1139/o67-133

Cited by 190 publications

(66 citation statements)

References 16 publications

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“…The trypsinsensitive sequence at the connecting region between glucagon and the COOH-terminal portion of peptide B7, however, is not unlike connecting sequences for various other polypeptide hormone precursors. Trypsin-like enzymes can account at least lpartially for conversion of proparathyroid hormone to parathyroid hormone (27), large gastrin to gastrin (6), g3-lipotrophin to 3-melanocyte-stimulating hormone (28), and proinsulin to insulin (2). The potential tryptic cleavage between residues 30 and 31 of peptide B7, however, would result in the production of glucagon with a COOH-terminal lysine residue.…”

Section: Discussionmentioning

confidence: 99%

Isolation of a Glucagon-containing Peptide: Primary Structure of a Possible Fragment of Proglucagon

Tager

Steiner

1973

Proc. Natl. Acad. Sci. U.S.A.

151

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The heterogeneity of crystalline bovine (ox)/porcine glucagon has been examined by gel filtration and ion-exchange chromatography. A strongly basic peptide that reacted well with antibodies to bovine/porcine glucagon was isolated and its primary structure was determined. The amino-acid sequence of the NH2-terminal 29 residues of the 4500-dalton peptide is identical with that of intact bovine or porcine glucagon. The remaining eight residues at its COOH-terminus are Lys-Arg-Asn-AsnLys-Asti-Ile-Ala. Small amounts of other glucagon-immunoreactive peptides having molecular weights ranging from 3700 to 9000 were also detected in crystals of bovine/ porcine glucagon. We propose that the 37-residue peptide is a fragment of bovine or porcine proglucagon.Accumulated evidence has suggested the existence of higher molecular weight precursor forms for several polypeptide hormones including insulin (1, 2), parathyroid hormone (3, 4), gastrin (5, 6), and glucagon (7-10). In 1970, Rigopoulou et al. reported that extracts of canine pancreas contain two components with glucagon-like immunoreactivity, the larger having a molecular weight of about 9000 (7). Studies of the biosynthesis of glucagon in islets of the anglerfish by Noe and Bauer showed that a 11,400-dalton component possessed several of the characteristics required for a biosynthetic precursor to glucagon (8,11). Other workers also have suggested the existence of biosynthetically labeled glucagon precursors in islets of pigeon (9) and guinea pig (10). None of these high molecular weight, glucagon-like substances, however, has been isolated or characterized chemically.Since proinsulin and several of its partially converted intermediate forms cocrystallize with insulin during the commercial preparation of that hormone (12, 13), we considered the possibility that small amounts of a glucagon precursor might be present in crystalline preparations of glucagon. Bromer et al. recently examined the heterogeneity of crystalline glucagon by ion-exchange chromatography (14), but limited their attention to the isolation and characterization of desamidoglucagon. Our studies proceeded from gel-filtration of crystalline bovine/porcine glucagon so that we might examine only those components larger than glucagon itself. MATERIALS AND METHODSMaterials. The glucagon used during these studies was a mixture of the bovine and porcine hormones. The crystalline preparation was purchased from ELANCO Products Co., Indianapolis, Ind. (lot no. 6PK72B) and is of pharmaceutical quality.Isolation of Peptides. 1 g of crystalline glucagon was filtered through Bio-Gel P-30 with 3 M propionic acid as the eluting solvent. Two early-eluting peaks of UV absorbance were separately pooled, and the fractions were concentrated by rotary evaporation. Each of the pools was then chromatographed on a column of SP-Sephadex C-25 using 5 mM sodium acetate buffer (pH 4.0), 8 M in freshly deionized urea, with a series of salt gradients eventually reaching 1 M in NaCl.Appropriate peaks of UV absorbance were poole...

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Section: Discussionmentioning

confidence: 99%

Isolation of a Glucagon-containing Peptide: Primary Structure of a Possible Fragment of Proglucagon

Tager

Steiner

1973

Proc. Natl. Acad. Sci. U.S.A.

151

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“…Residues 25-32 (underlined) were later corrected by Riniker et al (1972) The fifth peptide is γ-LPH. While sequencing of β-LPH, Chrétien and Li (1967) discovered another peptide with similar biological properties; they named it γ-LPH. Its sequence corresponded to residues 1-58 of β-LPH, ending with the β-MSH sequence.…”

Section: Figurementioning

confidence: 99%

“…The prohormone theory was based on the observation that β-lipotropin (β-LPH) and γ-lipotropin (γ-LPH) (Chrétien & Li 1967) contained the entire sequence of β-melanocyte-stimulating hormone (β-MSH), a pituitary octadecapeptide discovered 10 years earlier (Geschwind et al 1956, Harris & Roos 1956.…”

Section: Introductionmentioning

confidence: 99%

“…Retroactively, the prohormone theory could have been formulated one decade earlier when Li and co-workers, adopting the Sanger's fluorodinitrobenzene (FDNB) method (Sanger 1945) and the Edman's phenyl thiohydantoins (PTH) procedure (Edman 1950), sequenced several pituitary peptides including adrenocorticotrophic hormone (ACTH) (Li et al 1955), MSHs (Geschwind et al 1956, Harris & Lerner 1957, β-LPH (Li et al 1965), and γ-LPH (Chrétien & Li 1967). In the early 1970s, different groups provided evidence hinting that all these molecules were linked to one another.…”

Section: Introductionmentioning

confidence: 99%

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60 YEARS OF POMC: From the prohormone theory to pro-opiomelanocortin and to proprotein convertases (PCSK1 to PCSK9)

Chrétien

Mbikay

2016

Journal of Molecular Endocrinology

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Pro-opiomelanocortin (POMC), is a polyprotein expressed in the pituitary and the brain where it is proteolytically processed into peptide hormones and neuropeptides with distinct biological activities. It is the prototype of multipotent prohormones. The prohormone theory was first suggested in 1967 when Chrétien and Li discovered γ-lipotropin and observed that (i) it was part of β-lipotropin (β-LPH), a larger polypeptide characterized 2 years earlier and (ii) its C-terminus was β-melanocyte-stimulating hormone (β-MSH). This discovery led them to propose that the lipotropins might be related biosynthetically to the biologically active β-MSH in a precursor to end product relationship. The theory was widely confirmed in subsequent years. As we celebrate the 50th anniversary of the sequencing of β-LPH, we reflect over the lessons learned from the sequencing of those proteins; we explain their extension to the larger POMC precursor; we examine how the theory of precursor endoproteolysis they inspired became relevant for vast fields in biology; and how it led, after a long and arduous search, to the novel proteolytic enzymes called proprotein convertases. This family of nine enzymes plays multifaceted functions in growth, development, metabolism, endocrine, and brain functions. Their genetics has provided many insights into health and disease. Their therapeutic targeting is foreseeable in the near future. Thus, what started five decades ago as a theory based on POMC fragments, has opened up novel and productive avenues of biological and medical research, including, for our own current interest, a highly intriguing hypocholesterolemic Gln152His PCSK9 mutation in French-Canadian families.

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“…In the late sixties, Steiner et al [1] (demonstrating insulin production from proinsulin) and Chrétien and Li [2] (showing that the sequence of β-melanotropin is found in β-and γ-lipotropin) independently established first biochemical evidence for the maturation of hormones from precursors. Today seven mammalian basic amino acid sequence subtilisin/kexin-like proprotein convertases (PCs or PCSKs) are known as PCSK1, PCSK2, PCSK3 (also called furin), PCSK4, PCSK5 (also called PC5/6), PCSK6 (also called PACE4) and PCSK7 [3].…”

mentioning

confidence: 99%

Time for endothelial cell proprotein convertase PC5/6 in cardiovascular medicine?

Fritzsche

Stawowy

2011

J Mol Med

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ISOLATION, PURIFICATION, AND CHARACTERIZATION OF Γ-Lipotropic HORMONE FROM SHEEP PITUITARY GLANDS

Cited by 190 publications

References 16 publications

Isolation of a Glucagon-containing Peptide: Primary Structure of a Possible Fragment of Proglucagon

Isolation of a Glucagon-containing Peptide: Primary Structure of a Possible Fragment of Proglucagon

60 YEARS OF POMC: From the prohormone theory to pro-opiomelanocortin and to proprotein convertases (PCSK1 to PCSK9)

Time for endothelial cell proprotein convertase PC5/6 in cardiovascular medicine?

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