PubMed Health⌕ Search

Biomedical subjects

L Moroder

Publications and source records attributed to L Moroder.

At least 181 records · Page 10Linked to original sources
PubMed1976

Near-ultraviolet difference absorption and circular dichroism studies on partially synthetic ribonucleases S'.

Near-ultraviolet difference absorption and circular dichroism (CD) spectra were recorded upon recombination of synthetic S-peptide analogs, i.e. 1epsilon, 7epsilon-diguanidino-[Tyr8]-,1epsilon,7epsilon-diguanidono-[Asn14]-, [Phe(F)8, Orn10]- and 1epsilon, 7epsilon-diguanidino-S-peptide, with S-protein. Environmental alterations of Phe-8 in the S-peptide and Tyr-25 in the S-protein, derived from the association process, lead to strong optical signals whose location and magnitude were clearly defined by means of a comparative analysis of the above spectra. Additionally, the spectroscopic effects resulting from insertion of a tyrosyl residue into an hydrophobic environment in the presence or absence of hydrogen-bonding partners were identified and compared with similar findings obtained from the model compound p-cresol.

Circular Dichroism↗
PubMed1976

Far-ultraviolet difference absorption and circular dichroism studies on partially synthetic ribonucleases S'.

Far-ultraviolet difference absorption and circular dichroism (CD) spectra were recorded upon recombination of synthetic S-peptide analogs, i.e. 1epsilon, 7epsilon-diguanidino-[Tyr8]-, 1epsilon, 7epsilon-diguanidino-[Asn14]-, [Phe(F)8, Orn10]-, [Cha8, Orn10]- and 1epsilon, 7epsilon-diguanidono-S-peptide, with S-protein. The aromatic chromophores contributions to the absorption spectra in the 220-250 nm wavelengths interval strongly exceed the hyperchromism due to the random coil to right handled alpha-helix transition of the S-peptide, accompanying the association process. Contributions resulting from peptide transitions constitute a large portion of the total dichroism, nevertheless substitution of the non aromatic cycloexylalanine residue in position 8 of the S-peptide with phenylalanine, p-fluorophenylalanine and tyrosine leads to CD negative maxima located at 215, 215 and 212,5 nm, respectively. The strongest ellipticity increment (28%), relative to that of the Cha-derivative, was observed at 212,5 nm for the [Tyr8]-S-peptide analog, while in the narrow 222 nm range minimal differences were found upon insertion into the position 8 of the S-peptide of the above aromatic residues. Information derived from above data and from a comparison of RNAase A, S and S-protein CD spectra enabled us to assign the positive CD band at 240 nm in RNAase A spectrum to transitions of phenylalanines and inaccessible tyrosines.

Circular Dichroism↗
PubMed1976

Superior immunoreactivity of 125I (Des-Tyr-betaAla)-secretin with rabbit anti-secretin sera compared to 125I-secretin and 125 I-6-Tyrosyl secretin.

A secretin analogue in which the normal amino acid sequence had been elongated by a (Des-Tyr-betaAla)-residue was studied as tracer for secretin radioimmunoassay. 125I-(DATA)-secretin exhibited superior immunoreactivity with several rabbit anti-secretin sera compared to 125I-6-Tyr-secretin and also to secretin iodinated at its N-terminal histidyl residue. This may be due, at least in part, to higher conformational integrity of the secretin moiety in the 125I-(DATA)-secretin molecule. Thus, at present, 125I-(DATA)-secretin appears to be most suitable as tracer for sensitive secretin radioimmunoassay.

Amino Acid Sequence↗
PubMed1976

[1-Adamanty fluoroformate, a useful reagent in peptide chemistry (author's transl)].

1-Adamantyl fluoroformate was prepared from 1-adamantol and fluorophosgene. The cristalline and stable fluoroformate was allowed to react with amino acids to give the corresponding 1-adamantyloxycarbonyl derivatives in consistently high yields. Additonally this new reagent proved to be ideally reactive for acylation of the imidazol function of histidine and histidyl-peptides.

Acylation↗
PubMed1976

[Redioimmunoassay for secretin (author's transl)].

The synthesis of a secretin with an elongated N-terminus, namely Nalpha-(deaminotyrosyl-beta-alanyl)- secretin (DATA-secretin), using a conventional strategy, is described. After purification of the product by means of ion exchange chromatography on SP-Sephadex C-25 and by continuous carrier-free electrophoresis, immunological studies on the synthetic DATA-secretin were carried out using secretin antibodies. In comparison to 125iodine-labelled secretin and [Tyr6]secretin, 125iodine-DATA-secretin proved to be by far the best "tracer". Elaboration of a radioimmunoassay for secretin is therefore possible.

Animals↗
PubMed1975

Relation between structure and function in some partially synthetic ribonucleases S'. Enzymic and spectroscopic investigation on [Orn10, Asn14]-RNase S' and 1epsilon, 7epsilon, 10delta-triguanidino-[Orn10, Asn14]-RNase S'.

Some analogues have been prepared of S-peptide, the peptide obtained together with S-protein from subtilisn-modified beef pancreatic R Nase A. The syntheses are described of [Orn10, Asn14]-S-peptide and 1epsilon, 7epsilon, 10delta-triguanidino-[Orn10, Asn14]-S-peptide. The S-peptide analogues are able to activate S-protein at the level of the parent [Orn10]-S-peptide and 1epsilon, 7epsilon-diguanidino-S-peptide respectively, although at high peptide-to-protein molar ratios. After their recombination with S-protein the buried character of Tyr-25 was restored, as judged from difference absorption and circular dichroism spectra in the near-ultraviolet region. These findings indicate that the asparaginyl residue is a possible naturally occurring substituent in the R Nase A sequences whose state of amidation in position 14 has not yet been defined.

Amino Acid Sequence↗