David Chung

Isolation, characterization and opiate activity of β-endorphin from human pituitary glands

The isolation of a 31-amino acid peptide from human pituitary glands has been described. Its amino acid sequence has been proposed to be identical to the sequence of the carboxyl-terminal 31 amino acids of human β-lipotropin. The peptide, designated as βh-endorphin, possesses significant opiate activity.

Amino acid sequence of human chorionic somatomammotropin.

The complete amino acid sequence of the HCS molecule has been elucidated. The proposed structure is shown in Fig. 4. It consists of 191 amino acid residues with two disulfide bridges formed by residues 53–165 and 182–189.

Isolation and primary structure of β-endorphin and β-lipotropin from bovine pituitary glands

Summary Bovine pituitary β-endorphin has been isolated and its amino acid sequence shown to be identical with that of residues 61–91 in the ovine β-lipotropin structure. In addition, the primary structure of bovine β-lipotropin was found to consist of 91 amino acids, rather than 93 amino acids as previously reported.

Primary structure of the human chorionic somatomammotropin (HCS) molecule.

The complete amino acid sequence of the human chorionic somatomammotropin molecule been proposed; and then compared with that of human growth hormone and ovine lactogenic hormone.

β-Endorphin: Structure-activity relationships in the guinea pig ileum and opiate receptor binding assays

Abstract The opiate activities of some derivatives and enzymatic digests of camel and human β-endorphin were determined in the guinea pig ileum and rat brain opiate receptor binding assays. Derivatives of β-endorphins altered within the amino-terminal five residues showed pronounced losses in activity. Anisylation of the C-terminal glutamic acid residue of βh-endorphin produced only small reductions in activity. Chymotryptic digestion greatly weakened the opiate activities of βh-endorphin, whereas carboxypeptidase A, tryptic and leucine aminopeptidase digests showed only small losses in potency. The C-terminus of β-endorphin appears to contribute little directly to opiate activity. Amino acid analysis and assay of the leucine aminopeptidase digests suggest that the larger potency of β-endorphin relative to Met-enkephalin may be a consequence of its greater resistance to exopeptidase attack.

Adrenocorticotropin 53. The amino acid sequence of the hormone from the ostrich pituitary gland

Abstract The amino acid sequence of corticotropin from the ostrich pituitary gland has been determined. It consists of 39 amino acids with the following sequence: H-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-Gly-Arg-Lys-Arg-Arg-Pro-Val-Lys-Val-Tyr-Pro-Asn-Gly-Val-Gln-Glu-Glu-Thr-Ser-Glu-Gly-Phe-Pro-Leu- Glu-Phe-OH. This is the first report on the primary structure of corticotropins from avian species.

The primary structure of monkey pituitary growth hormone.

Monkey growth hormone (MGH) has been purified by reverse-phase high-performance liquid chromatography (HPLC). Tryptic digests of MGH were separated by HPLC and paper electrophoresis. From amino acid composition, from NH2-terminal residue and sequence analyses of these tryptic peptides, and from their alignment with those of human growth hormone, the primary structure of MGH was proposed. There are only four residues which are different in these two growth hormone molecules.

β-endorphin: Primary structure of the hormone from the ostrich pituitary gland

Abstract The amino acid sequence of β-endorphin from the ostrich pituitary has been determined. It consists of 31 amino acids with high opiate receptor-binding activity. The proposed sequence is as follows: H-Tyr-Gly-Gly-Phe-Met-Ser-Ser-Glu-Arg- Gly-Arg-Ala-Pro-Leu-Val-Thr-Leu-Phe-Lys-Asn-Ala-Ile-Val-Lys- Ser-Ala-Tyr-Lys-Lys-Gly-Gln-OH. When compared with the primary structures of other known β-endorphins, it is the first instance that residues in positions 6, 9, 10, 11, 12 and 25 are different.

The primary structure of ovine interstitial cell-stimulating hormone III: Disulfide bridges of the α-subunit

Abstract The disulfide linkage of the ten half-cystine residues in the α-subunit of ovine interstitial cell-stimulating hormone has been investigated by partial acid and enzymic hydrolysis of the intact molecule. Results indicate that the disulfide bridges are formed by residues 14–86, 11–64, 35–63, 32–89, and 36–91.

Isolation and characterization of δ-melanotropin, a new peptide from bovine pituitary glands

Abstract A new melanotropin (MSH) was isolated from bovine pituitary extract by means of gel filtration, ion exchange chromatography, high performance liquid chromatography and paper electrophoresis. Amino terminal analysis, amino acid composition and tryptic hydrolysis were performed on the purified peptide. The peptide was found to contain the amino acid sequence of γ-MSH, a theoretical segment of the proopiomelanocortin molecule. However, theoretical segment of the proopiomelanocortin molecule. However, the new peptide differs from the γ-MSH in several major ways, thus it is designated a bovine δ-MSH or δ b -MSH.