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Biomedical subjects

B Peeters

Publications and source records attributed to B Peeters.

At least 91 records · Page 5Linked to original sources
PubMed1976

Synthesis of human placental lactogen in Xenopus oocytes.

Oocytes from Xenopus laevis were injected with polysomes from normal human term placenta. Synthesis of the protein hormone Human Placental Lactogen (HPL) in the oocytes was demonstrated by specific immunoprecipitation with anti-HPL serum. Analysis of the immunoprecipitates on SDS-polyacrylamide gel revealed one peak, with a migration distance corresponding exactly to that of [14C]-Radioacetylated HPL added as a marker. Two days after injection the mRNA was still able to direct the synthesis of HPL.

Animals↗
PubMed1976

The synthesis of human placental lactogen hormone (hPL) in a cell-free wheat germ system.

Total polysomes from human term placenta were incubated in a wheat germ cell-free system during 1 hr at 25 degrees C. Human placental lactogen hormone was identified among the proteins synthesized in vitro by immune precipitation and subsequent sodium dodecylsulphate electrophoresis of the immunoprecipitate. The zone containing the radioactivity from the immunoprecipitate [3H]-labelled lactogen hormone comigrated exactly with the radioactivity zone from added [14C]-labelled marker hormone. This result indicates that the molecular weight of the synthesized product must be equal or very similar to that of the native protein hormone.

Carbon Radioisotopes↗
PubMed1975

Isolation and characterization of active ribosomal subunits from human placenta.

We have developed a method for the large-scale isolation of active ribosomal subunits from human placenta. The technique involves incubating crude ribosomes for 15 min at 37 degrees C with 0.2 mM puromycin in 50 mM Tris-HCl buffer, pH 7.6, 500 mM KCl and 3 mM MgCl2 followed by centrifugation at 5 degrees C in a BXV zonal rotor using an equivolumetric sucrose gradient in the same buffer, upon which 80--90% of all ribosomes are dissociated into subunits. The purified subunits differ in their chemical composition, the 60-S particle containing no more than 36% protein whereas the 40-S subunit consists of 43% protein. In poly(U)-directed protein synthesis, tested in a completely homologous cell-free system, one recombined couple polymerizes at 37 degrees C 12 to 17 phenylalanine residues at an initial rate of 0.7 residues per minute. However, free 80-S ribosomes obtained by puromycin treatment of the crude ribosomes and reassociation of the subunits without prior isolation, have an even higher incorporating activity (20--25 mol phenylalanine/mol of ribosome). At least 55% of the subunits were estimated to actively participate in the polyphenylalanine synthesis.

Cell Fractionation↗
PubMed1975

Determination of the complete amino acid sequence of protein S21 from Escherichia coli ribosomes.

Protein S21 was digested with trypsin before and after maleylation, with chymotrypsin, thermolysin and a glutamyl-specific protease. The resulting peptides were isolated and their amino acid composition determined. The amino acid sequences of selected peptides were determined either by the manual subtractive Edman method or by the dansyl-Edman procedure. Additional information was obtained from the automatic Edman degradation of the whole protein in a modified Sequenator. All these results combined yielded the sequence shown in Fig. 1. Protein S21 consists of 70 amino acids (Asp1,Asn2,Thr3,Ser2,Glu8,Pro3,Gly1,Ala9,Val6,Cys1,Ile1,Leu4,Tyr2,Phe3,His1,Lys9 and Arg14). It contains neither Met nor Trp. The molecular weight amounts to 8359. Clustering of basic amino acids is observed in five regions. We also include a prediction for regions with alpha-helices and with beta-sheets.

Amino Acid Sequence↗