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Biomedical subjects

D Yamashiro

Publications and source records attributed to D Yamashiro.

At least 91 records · Page 5Linked to original sources
PubMed1977

Synthesis and biological activity of beta-melanotropins and analogues.

Synthetic [Arg8]-, [Gly10]-, and [Phe12]-beta cl-MSH and beta p-MSH have been prepared by the solid-phase method. Their lipolytic and melanotropic activities have been compared to each other and with those of previously synthesized beta cl-MSH, [formyl-Trp12]-beta cl-MSH, and beta b-MSH. Replacement of Bln8 of beta cl-MSH by Arg causes a greater decrease in melanotropic activity than lipolytic activity. However, when Phe10 of beta cl-MSH is replaced by Gly, both activities are destroyed. Alteration or replacement of Trp12 of beta cl-MSH by formyl-Trp or Phe has little effect on the melanotropic activity while the lipolytic activity is greatly decreased. Replacement of Ser2 of beta b-MSH by Glu induces a three fold increase in melantropic activity but it does not affect the lipolytic activity.

Animals↗
PubMed1977

Synthesis and analgesic activity of human beta-endorphin.

The solid-phase synthesis of human beta-endorphin is described. A yield of 32% is achieved based on starting resin. The synthetic product behaves as a homogeneous peptide in partition chromatography, paper electrophoresis, thin-layer chromatography, disc electrophoresis, amino acid composition, and a tryptic map. The synthetic beta h-endorphin possesses antinociceptive properties as estimated by the tail-flick, hot-plate, and writhing tests in mice. When applied centrally, beta h-endorphin is 17-48 times more potent than morphine. It is 3.4 times more potent than morphine when injected intravenously. The analgesic responses are blocked by the specific opiate antagonist, naloxone.

Amino Acid Sequence↗
PubMed1977

beta-endorphin: synthesis and morphine-like activity of analogs with D-amino acid residues in positions 1, 2, 4, and 5.

The solid-phase syntheses of [D-Tyr1]-, [D-Ala2]-, [D-Phe4]- and [D-Met5]-beta c-endorphins are described. A comparison of certain methods of purification and criteria of homogeneity is made with the use of these compounds. Bioassay of these synthetic analogs both in vitro and in vivo show that [D-Ala2]-beta c-endorphin possesses significant opiate activity whereas the other analogs have minimal activity.

Amino Acid Sequence↗
PubMed1977

Human somatotropin 53. Synthesis and biological activity of the amino terminal fifty-four residue fragment.

The amino terminal 54 residue peptide fragment of human somatotropin [Cys(Gam)53]-HGH-(1-54), has been synthesized by the solid-phase method. The symmetrical anhydride and active ester coupling methods were used exclusively. The synthetic product was purified by gel fitration isoelectric focusing, and partition chromatography. It was found to be homogeneous by six additional criteria. In complement fixation experiments the synthetic product was immunologically active with antisera to HGH and [cys(Cam)53]-HGH-(134). Antiserum raised against the synthetic product was immunologically active in the homologous assay and with HGH,[Cys(Cam)53]-HGH-(1-134), and [Cys(Cam)53]-HGH-(15-125). The synthetic fragment exhibited 53% of the activity of [Cys(Cam)53]-HGH-(1-134) in the rat tibia assay.

Amino Acid Sequence↗
PubMed1976

Synthesis and biological activity of camel and bovine beta-melanotropins.

Two natural occurring melanotropins, camel betaC2-MSH and bovine beta-MSH, have been synthesized by improved solid-phase procedures. The coupling reaction of tert-butyloxycarbonylamino acids was achieved by using their preformed symmetrical anhydrides. The synthetic hormones were purified by gel filtration on Sephadex G-10 and G-25, chromatography on carboxymehtylcellulose, and partition chromatography on Sephadex G-25 with final yields of 56 and 35% for betac2-MSH and betab-MSH, respectively. They were then shown to be identical with their natural hormones in amino acid analysis, paper electrophoresis, disc electrophoresis, thin-layer chromatography, enzymic digests, and bioassays. Bioassay data of these two synthetic melanotropins indicate that the replacement of Ser by Gly in betab-MSH does not change its melanocyte-stimulating activity.

Animals↗
PubMed1975

Pituitary lactogenic hormone. XXXVII. Synthesis and properties of the carboxyl terminal cyclic undecapeptide.

The carboxyl terminal cyclic undecapeptide of the ovine prolactin molecule: Leu-Asn-Cys-Arg-Ile-Ile-Tyr-Asn-Asn-Asn-Cys has been synthesized by the solid-phase method. The circular dichroism of the synthetic peptide has been investigated. It was also found that the cyclic undecapeptide does not have pigeon crop-sac stimulating activity, or immunological activity when tested by complement fixation experiments.

Animals↗
PubMed1974

Synthesis of a pentekontapeptide with high lipolytic activity corresponding to the carboxyl-terminal fifty amino acids of ovine beta-lipotropin.

The synthesis of a peptide, composed of fifty amino-acid residues, corresponding to positions 42-91 in ovine beta-lipotropin has been accomplished by the solidphase method. The preformed symmetrical anhydride and active ester coupling methods were used exclusively. The synthetic product was purified by gel filtration, carboxymethylcellulose chromatography, and partition chromatography on Sephadex G-50. Its lipolytic activity in isolated rabbit fat cells was about six times that of beta-lipotropin on a weight basis.

Adipose Tissue↗