Fritz Raschdorf

Separation, purification, and sequence identification of TGF-β1 and TGF-β2 from bovine milk

Cox and Bürk (Eur. J. Biochem., 1991) reported the partial characterization of Milk Growth Factor (MGF) which stimulated the migration of fibroblasts. We have fractionated the partially purified sample by RP-HPLC and obtained the separation of two peaks of activity. The two active components were isolated as pure MGF-a and MGF-b by RP-HPLC and preparative SDS-PAGE. The purified MGF-a, consisting of a single band by gel electrophoresis and a single peak on an HPLC reversed-phase C-4 column, has the same specific activity as TGF-β2 in the fibroblast migration assay. MGF-a was digested by endoprotease Asp-N and the cleaved peptides were analyzed by Edman degradation and plasma desorption mass spectrometry (PDMS). The whole sequence of MGF-a determined by automated sequenator and PDMS of S-pyridylethylated protein and selected fragments was found to be identical to that of TGF-β2. MGF-b protein mixture separated by SDS-PAGE was electrophoretically transferred onto a Biometra Glassybond membrane, and the blotted MGF-b protein was directly sequenced on an automated sequenator. The identified 29 amino acids sequence of MGF-b was identical to the amino-terminal sequence of TGF-β1. Our study demonstrates that MGF is composed of both TGF-β1 and TGF-β2. TGF-β2 (85%) is the predominant form.

Conversion of NGurethane protected arginine to ornithine in peptide solid phase synthesis

Abstract It is shown that Di-Adoc or Boc as guanidino protecting groups do not prevent the acylation and the subsequent conversion of arginine to ornithine in Fmoc solid phase peptide synthesis.

Isolation and purification of novel hirudins from the leech Hirudinaria manillensis by high-performance liquid chromatography.

The isolation and purification of novel hirudins from a crude extract of the leech Hirudinaria manillensis and their analytical characterization are reported. Initial purification by gel permeation chromatography on Sephadex G50 and anion-exchange chromatography on Q Sepharose fast-flow removed most contaminants and yielded a highly active extract. Two isohirudins (designated hirudin P6 and P18) were isolated and purified by successive reversed-phase high-performance liquid chromatography on silica-based stationary phases and anion-exchange chromatography on Mono Q. The final products were characterized by reversed-phase high-performance liquid chromatography, 252Cf plasma desorption time-of-flight mass spectrometry and capillary zone electrophoresis. The molecular masses determined by 252Cf plasma desorption mass spectrometry were 7416 dalton for hirudin P6 and 7199 dalton for hirudin P18.

Bipyridine-coupled permethylated β-cyclodextrin

Abstract The synthesis and characterization of a cyclodextrin dimer, obtained by connecting two permethylated β-cyclodextrins with a 2,2′-bipyridine ligand, and of its luminescent Re(I) metal complex are described. Such a system is of interest to study energy transfer between the active metal center and a bound ditopic substrate.

Chromatographic isolation and characterization of streptogramin antibiotics

Abstract High-performance and medium-pressure liquid chromatographic techniques were developed for the rapid isolaiton, identification and characterization of the components from crude virginiamycin and viridogrisein. Two new minor components, denoted virginiamycin S5 and viridogrisein II, were isolated. Their structures were determined by amino acids analysis and mass spectrometry. (I. Oberbaumer et al., Helv. Chim. Acta, 65 (1982) 2280).