Biomedical subjects
Publications and source records attributed to D Yamashiro.
Explore the source record for details and available documents.
gamma-Lipotropin has been purified to homogeneity from human pituitary glands. It consists of 56 amino acids with one residue each of Trp, Thr, Val, Tyr, and Phe. The amino acid sequence has been determined as follows: H-Glu-Leu-Thr-Gly-Gln-Arg-Leu-Arg-Gln-Gly-Asp-Gly-Pro-Asn-Ala-Gly-Ala-Asp-Asp-G ly-Pro-Gly-Ala-Gln-Ala-Asp-Leu-Glu-His-Ser-Leu-Leu-Val-Ala-Ala-Glu-Lys-Lys-Asp- Glu-Gly-Pro-Tyr-Arg-Met-Glu-His-Phe-Arg-Trp-Gly-Ser-Pro-Pro-Lys-Asp-OH. Comparison with the structure of the ovine and porcine hormones reveals that the 23-amino-acid sequence at the COOH terminus is highly conserved in evolution.
Biological activities of synthetic camel beta-endorphin and human beta-endorphin (beta h-EP) have been measured by the radioreceptor binding assay, using [Tyr27-3H]-beta h-EP as the primary ligand and by the tail-flick test for analgesic potency. Four synthetic analogs of beta h-EP, namely [Gly31]-beta h-EP-Gly-NH2, [Gly31]-beta h-EP-Gly-Gly-NH2, [Gln8,Gly31]-beta h-EP-Gly-Gly-NH2, and [CH3(CH2)4NH231]-beta h-EP, have also been assayed by the same procedures. Results indicate a clear dissociation of radioreceptor binding activity from analgesic potency.
An analog of human beta-endorphine with omission of four residues at positions 11, 14, 20, and 22 has been synthesized. This analog and other synthetic analogs with deletion of a single amino acid at position 2, 5, 6, 10, 11, 12, 13, 15, or 22 have been assayed for analgesic potency, ileal opiate activity,opiate receptor-binding activity, andimmunoreactivity. Results show that deletion of a single amino acid of the beta-endorphin molecule outside of the enkephalin segment to give des-Gln11-, des-Thr12, des-Pro13-, des-Leu14-, des-Val15-, des-Asn20-, or des-Ile22-beta-endorphin markedly reduced or abolished the immunoreactivity yet gave substantial retention of opiate potencies. Deletion of a single amino acid of beta-endorphin within the enkephalin segment (des-Gly3- or des-Met5-beta-endorphin) did not markedly affect the immunoactivity; however, the opiate activities were abolished or markedly reduced. The data indicate a clear dissociation of immunoactivity from analgesic, ileal-opiate, and opiate receptor-binding activities.
Four analogs of human beta-endorphin (beta h-EP) have been synthesized: [Gly31]-Beta h-EP-Gly-NH2, [CH3(CH2)4NH231]-beta h-EP, [Gly31]-beta h-EP-Gly-Gly-NH2, and [Gln8, Gly31]-betah-EP-Gly-Gly-NH2. All are more active than beta h-EP in an opiate receptor binding assay. Stepwise extension at the COOH-terminus shows a progressive increase in binding activity. The last analog, which combines extension at the COOH-terminus with elimination of the remaining anionic charge in beta h-EP, is nine times more active than the parent molecule.
Des-acetylated salmon endorphin and turkey beta-endorphin have been synthesized by the solid-phase method. Relative opiate activities in a radioreceptor binding assay are: human beta-endorphin, 100; des-acetylated salmon endorphin, 169; turkey beta-endorphin, 94. Thus, non-mammalian endorphins can show high activity in a mammalian assay system.
Explore the source record for details and available documents.
Three analogs of human beta-endorphin (beta h-EP) have been synthesized: [Gly31]beta h-EP, [Gly31]beta h-endorphinamide, and [Gly31]beta h-endorphinylglycine. All are more active than beta h-EP in both the guinea pig ileum bioassay and the opiate receptor binding assay. The last two analogs are about twice as active as beta h-EP in an assay for analgesia. Modification at position 31 and extension at the COOH terminus may afford a route toward analogs with even greater biological activity.
A study of the efficiency of partition chromatography for the purification of peptides as a function of structure has been undertaken. A series of 19 omission analogs of camel beta-endorphin and of some of its partial sequences have been synthesized with each analog missing only a single amino acid. Their chromatographic properties have been examined with use of the Martin hypothesis and the RM concept, and a hydrophobicity scale for the amino acid side chains was obtained. To a first approximation a correlation with the Tanford hydrophobicity scale for amino acids was found. A decrease in hydrophobicity has been observed with increasing chain length and is discussed in terms of column efficiencies required for the purification of synthetic peptides.
Explore the source record for details and available documents.
A corticotropin-inhibiting peptide (CIP) has been isolated from human pituitary extracts. It consists of 32 amino acids with a proposed sequence identical to residues 7--38 of corticotropin (ACTH). The peptide has been synthesized by the solid-phase method. The melanotropic activity of the peptide is estimated to be 30% of the potency of ACTH. It is devoid of corticosteroidogenic activity but is able to inhibit ACTH-stimulated corticosterone production in isolated rat adrenal cells.
Three analogs of beta-endorphin have been synthesized by the solid-phase method: betac-endorphin-(1--5)-(28--31), betac-endorphin-(6--31) and betah-endorphin-(1--5)-(16--31). The analgesic activities of these synthetic peptides relative to that of the parent molecule are reported. All three peptides at high doses exhibit either no or much weaker analgesic activity than beta-endorphin. These data suggest that the entire beta-endorphin molecule is necessary for full in vivo analgesic activity.
The 51-residue peptide ovine beta-lipotropin-(41--91) has been synthesized by the solid-phase method in about 5% overall yield. The synthetic product was characterized by partition chromatography on agarose gel, thin-layer chromatography in two solvent systems, paper electrophoresis at two pH values, polyacrylamide gel electrophoresis, amino acid analyses of acid and enzymic hydrolysates, and bioassay for lipolytic and melanotropic activities. The synthetic peptide is about 5.4 times as active on a weight basis as ovine beta-lipotropin in the lipolytic assay. In the melanotropic assay, it was about 2.4 times more active than the beta-lipotropin but only 5% as active as bovine beta-melanotropin. It had negligible opiate activity in the guinea pig ileum assay.
The solid-phase syntheses of [Sar2]-, [Ala2]-, [D-Leu2]-, [D-Lys2]-beta-endorphins and [Pro5]-, [Leu5]-, [D-Leu5]-, [D-Ala2, D-Leu5]-beta-endorphins are described. The synthetic peptides were purified by chromatography on carboxymethylcellulose and partition chromatography on Sephadex G-50. They were characterized by partition chromatography on agarose, thin-layer chromatography, paper electrophoresis, and amino acid analyses of acid and enzymic hydrolysates. Bioassay of the synthetic analogs for analgesic activity by the tail-flick method showed the D-Leu2 analog to be 48% as potent as betah-endorphin while the Ala2, D-Lys2, Leu5, and [D-Ala2, D-Leu5] analogs were 8 to 17% as active. The Sar2, D-Leu5, and Pro5 analogs were less than 1% as potent.
The synthesis of beta h-endorphin -(1--15), -(1--21), -(1--26), -(1--28) and -(1--29) have been accomplished by the solid-phase method. The opiate activities of the peptides were measured in the guinea pig ileum assay. Their relative potencies were beta h-endorphin (beta h-EP), 1.00; Met-enkephalin, 0.25: beta h-EP-(1--15), 0.17; beta H-EP-(1--21), 0.46; beta H-EP-(1-26), 0.48; beta h-EP-(1--28), 0.89; beta h-EP-(1--29), 1.04.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.