Biomedical subjects

T Inui

Publications and source records attributed to T Inui.

218 records · Page 13Linked to original sources

PubMedDate not supplied

Synthesis and disulfide structure determination of agelenin: identification of the carboxy-terminus as an amide form.

Agelenin, a blocker of the presynaptic calcium channel, is a 35-amino acid peptide having six cysteinyl residues recently isolated from the venom of the spider Agelena opulenta. However, it has not been confirmed whether the carboxy-terminus of this peptide is a free acid or amide. To elucidate this, we synthesized both peptides by a solid phase procedure, and compared their elution profiles with that of the natural product on RP-HPLC. The retention time on HPLC as well as the biological activity of the synthetic peptide-amide was found to be identical with those of natural agelenin, confirming that the carboxy-terminus of agelenin is amidated. The disulfide structure of agelenin was also determined to be linked between 3-19, 10-24 and 18-34, by comparing the tryptic peptide linked by two disulfide bonds with those synthesized by the selective formation of disulfide bonds.

Amides↗

PubMedDate not supplied

Suppression of a side reaction associated with N(im)-benzyloxymethyl group during synthesis of peptides containing cysteinyl residue at the N-terminus.

During the synthesis of His-containing peptide, having a Cys residue at the amino terminus, by the HF method, a large quantity of an unexpected product was formed when the His residue was protected by the benzyloxymethyl (BOM) group. This side product was found to be a thioprolyl-peptide which was formed from the Cys-peptide with formaldehyde released from the Bom group by HF. In order to suppress this side reaction, we tried using various scavengers and found that Cys and its derivatives were most effective, although they could not completely suppress the side reaction. Even after the HF reaction, formaldehyde attached to the scavenger or peptide seemed to cause further conversion of the Cys-peptide to thioprolyl-peptide. Thus, proper removal of the formaldehyde from the reaction mixture is essential to reduce the formation of this undesirable product.

Angiotensin II↗