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Biomedical subjects

P Ferrara

Publications and source records attributed to P Ferrara.

At least 217 records · Page 12Linked to original sources
PubMed1982

Beta-Endorphin. Interaction of synthetic analogs having different chain lengths with morphine and enkephalin receptors in rat brain membranes.

Human beta-endorphin analogs with various chain lengths have been investigated for their potency in displacing tritiated dihydromorphine and Leu-enkephalin binding in rat brain membrane preparations. It was found that the reduction of chain length from residues 1-31 to 1-5 led to a gradual loss of preference for the morphined receptor. In addition, the extension of the chain length of the Met-ekephalin segment to the COOH-terminal glutamic acid modified the binding of the NH2-terminal sequence to the enkephalin receptor. The fact that camel beta-endorphin is more potent in displacing the two tritiated primary ligands than the human hormone is also reported herein.

Amino Acid Sequence↗
PubMed1981

Opiate receptor-binding activity of [D-Thr2,Thz5]-and [D-Met2,Thz5]-enkephalinamides.

The binding characteristics of two highly potent analgesic enkephalin analogs, [D-Thr2, Thz5]-and [D-Met2, Thz5]-enkephalinamide, to the rat brain membrane preparation have been investigated using tritiated Leu-enkephalin, human beta-endorphin or dihydromorphine as the primary ligand. Concentrations for 50% inhibiting activity of the enkephalin analogs are much lower in displacing tritiated dihydromorphine in comparison with that for the other two tritiated ligands. In addition, a correlation between analgesic potency and capacity to displace tritiated dihydromorphine is observed. These data may explain the high antinociceptive activity of the enkephalin analogs and support the hypothesis that the mu-receptor is involved with analgesia.

Animals↗
PubMed1981

beta-Endorphin: characteristics of binding sites in a neuroblastoma--glioma hybrid cell.

Specific binding of human beta-endorphin to NG108-15 cells is described; human beta-[Tyr27-3H2] endorphin was used as the ligand. The binding is time dependent and saturable; Kd = 0.3 nM and ka = 1.8 x 10(8) M-1 min-1. Under the conditions optimal for beta-endorphin binding, leucine-enkephalin has one-fourth to one-third as many binding sites as beta-endorphin and its affinity is 7--10% that of beta-endorphin. Monovalent and divalent cations potently inhibit binding. Trypsin, phospholipase A, and N-ethylmaleimide reduce the ability of NG108-15 cells to bind beta-endorphin. beta-Endorphin analogs are able to fully inhibit the binding of beta-[Tyr27-3H2]endorphin, although enkephalins, morphine, and naloxone inhibit only 50--80%.

Animals↗
PubMed1981

Synthesis and properties of human growth hormone fragments.

The solid phase synthesis of fragments 75-120-NH2 and 73-128-GlyNH2 of the human growth hormone sequence is described. Purification was by solvent extraction, gel filtration and partition chromatography. No growth-promoting activity was detected in any of the peptides by the rat body-growth assay. An immunochemically reactive area was located in the sequence 73-128 when tested by complement fixation assays.

Amino Acid Sequence↗
PubMed1980

beta-Endorphin: characteristics of binding sites in rabbit spinal cord.

The interaction of human beta-endorphin with binding sites in rabbit spinal cord has been characterized. The stereospecific high-affinity binding sites are concentrated in the dorsal half of the spinal cord. Scatchard analysis of the binding data shows heterogeneity of the binding sites that can be resolved into two populations with apparent dissociation constants of 3.0 (+/-2.0) X 10(-10) and 3.3 (+/- 0.5) X 10(-9) M. Sodium ions decrease the binding of human beta-endorphin to spinal cord to the same extent as found in rat brain. The ability of several opiates and opioid peptides to inhibit the binding of human beta-endorphin is also presented.

Animals↗
PubMed1980

Beta-Endorphin: dissociation of receptor binding activity from analgesic potency.

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.

Amino Acid Sequence↗
PubMed1980

beta-Endorphin omission analogs: dissociation of immunoreactivity from other biological activities.

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.

Animals↗
PubMed1980

beta-endorphin: synthesis of analogs with extension at the carboxyl terminus with high radioreceptor binding activity.

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.

Amino Acid Sequence↗
PubMed1980

beta-Endorphin: radioreceptor binding assay. Relative potency of synthetic analogs with various chain lengths.

An assay system is described to measure the specific binding of beta-endorphin to opiate sites (receptors) in rat brain membrane preparations using the tritiated hormone as the primary ligand. By this assay procedure, the radioreceptor activity of beta-endorphin and synthetic analogs with various chain lengths has been determined. The results suggest that both NH2- and COOH-terminal sequences of the molecule are involved in the interaction of beta-endorphin with opiate receptors.

Animals↗
PubMed1979

Immunologically active zones in bovine growth hormone.

Antigenic determinant areas were detected in bovine growth hormone fragments 6--124 and 125--149, the former being predominant. Reduction and carboxymethylation of disulfide bridge 53--164 destroys the immunological reactivity of the area which is little affected by reduction and carbamoylmethylation. All the activity found in fragment 6--124 seems to be concentrated in the sequence 87--124.

Animals↗
PubMed1979

beta-Endorphin: synthesis of analogs modified at the carboxyl terminus with increased activites.

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.

Analgesics↗