Biomedical subjects

F S Tjoeng

Publications and source records attributed to F S Tjoeng.

22 records · Page 2Linked to original sources

PubMed1985

Differential structure-activity relationships of atrial peptides as natriuretics and renal vasodilators in the dog.

Natriuretic-diuretic and vasodilator activities of synthetic atriopeptin (AP)-related peptides were examined in the anesthetized dog. We have selected, the naturally occurring, APIII as the reference compound for comparison with various related peptides. APIII is a 24 amino acid peptide with the sequence ser-ser-cys-phe-gly-gly-arg-ile-asp-arg-ile-gly-ala-gln-ser-gly-leu-gly- cys-asn-ser-phe-arg-tyr-OH. APII, another peptide isolated from atrial extracts, lacks the C-terminal arg- of APIII. N-terminal amino acid extensions on APIII or APII, exhibited enhanced natriuretic-diuretic effectiveness. Furthermore, the maximum response obtained by ser-leu-arg-arg-APIII and arg-arg-APIII were significantly higher and the dose-response curve was not parallel to that obtained with APIII. In contrast, there were no significant qualitative or quantitative differences between the renal blood flow responses produced by the N-terminal extended peptides and APII or APIII. These results suggest a heterogeneity of AP receptors in vascular and renal tubular tissues.

Amino Acid Sequence↗

PubMed1983

Synthesis of the protected tridecapeptide (56-68) of the VH domain of mouse myeloma immunoglobulin M603 and its reattachment to resin supports.

A protected tridecapeptide, representing a new peptide corresponding to residues 56-68 of the VH domain in the mouse M603 myeloma protein, has been prepared by solid phase peptide synthesis. The protected tridecapeptide was prepared using the photolabile 4-bromomethyl-(3-nitro)-benzamidomethyl-resin and the multidetachable 2-[4-bromomethyl)phenylacetoxy]propionyl-resin as solid supports. The synthetic protocol and protecting groups were the same for both syntheses. The protected tridecapeptide was removed photolytically from both supports and the sequence integrity was determined by preview analysis using the solid phase Edman degradation procedure. The protected tridecapeptide-OMPA was purified to homogeneity by DMF/H2O precipitation and LH-60 chromatography. The purity of the protected peptide was further demonstrated by high pressure liquid chromatography on the free peptide after HF deprotection. The protected tridecapeptide was reattached to 4-bromomethyl-(3-nitro)-benzamidomethyl-resin to give the photolabile Boc-(protected)peptidyl-4-oxymethyl-(3-nitro)benzamidomethyl-resin in 25% yield. The protected tridecapeptide-oxymethylphenylacetic acid derivative was reattached to aminomethyl-resin to give Boc-(protected)peptidyl-2-[4-oxymethyl)phenyl]acetamidomethyl-resin in 45% yield and to 2-bromopropionyl-resin generating the multidetachable Boc-(protected)peptidyl-2-[(4-oxymethyl)phenylacetoxy] propionyl-resin in 80% yield. The reactivity of these reattached peptides was demonstrated by the quantitative coupling of Boc-leucine to the protected peptide-resin. The advantages and disadvantages of the different resins with respect to solid phase fragment synthesis are discussed.

Amino Acid Sequence↗

PubMed1979

Solid phase synthesis of the protected 27--42 hexadecapeptide of the heavy chain from myeloma immunoglobulin M603. Elimination of side reactions associated with glycyl-2-oxypropionyl-resin.

A fully protected 27--42 hexadecapeptide of the variable region of myeloma immunoglobulin M603 was synthesized on a 2-bromopropionyl-resin by the solid phase method. Side reactions due to cyclization of glycyl-2-oxypropionyl-resin were studied under different reaction conditions. The loss of peptide chains at the dipeptide and tripeptide stages due to diketopeperazine formation was also examined. These side reactions were circumvented by using a combination of fragment and stepwise coupling methods. The synthesized protected peptide was removed from the resin in 85% yield by photolysis, and purified by crystallization and by chromatography on a Sephadex LH-60 column.

Amino Acid Sequence↗

PubMed1977

Liquid-phase method for peptide synthesis utilizing photolytic cleavage from a new o-nitrobenzoyl polyethylene glycol support.

Photolysis as a method for removal of a tert-butyloxycarbonyl-protected peptide possessing a free C-terminal carboxyl group from a polystyrene support in the solid-phase method of peptide synthesis was introduced by Rich, D. H. and Gurwara, S. K.((1975) J. Am. Chem. Soc. 97, 1575-1578). Using this basic concept we prepared a photosensitive 3-nitro-4-bromomethylbenzoyl polyethylene glycol support for use in the liquid-phase method of peptide synthesis. Photolytic cleavage of a protected tetrapeptide possessing a free C-terminal carboxyl group from the polyethylene glycol support resulted in a 98% yield compared with a 69% yield for the photolytic leavage from the polystyrene support. This application of photolysis as a cleavage method in liquid-phase peptide synthesis avoids the low yields and rather drastic conditons needed to remove a peptide attached directly to the poly-ethylene glycol support in the conventional liquid-phase method.

Alanine↗