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W Rombauts

Publications and source records attributed to W Rombauts.

At least 73 records · Page 4Linked to original sources
PubMed1982

Study of a proline-rich polypeptide bound to the prostatic binding protein of rat ventral prostate.

A proline-rich polypeptide is associated with prostatic binding protein, a major androgen-dependent protein described previously in the rat ventral prostate. This polypeptide has been purified. Its molecular weight estimated by gel filtration is about 8500, but a markedly lower value (3300) is obtained by sodium dodecyl sulfate-urea polyacrylamide gel electrophoresis. Isoelectric focusing on thin layer polyacrylamide gels yields two major forms with isoelectric points of, respectively, 7.75 and 7.05. The amino acid composition of proline-rich polypeptide is characterized by a high (19.5%) proline content and its NH2-terminal amino acid is glycine. Like prostatic binding protein, proline-rich polypeptide is a characteristic component of the rat ventral prostate and localized primarily in the intraluminal secretion of this gland. In intact adult male rats the cytosol of a whole gland contains 0.70 +/- 0.15 (S.D.) mg of the polypeptide, as measured by radial immunodiffusion or 2.6 +/- 0.5% of (S.D.) of the total protein. This amount decreases gradually after castration and becomes undetectable after 8 days. Androgen treatment, on the other hand, results in a rapid stimulation, while estradiol and progesterone are ineffective. Proline-rich polypeptide is markedly more androgen-dependent than prostatic binding protein, and promises to be an interesting end point for studies on the mechanism of action of androgens.

Amino Acids↗
PubMed1982

Structural studies on rat prostatic binding protein. The primary structure of component C1 from subunit F.

The amino acid sequence of component C1, the polypeptide specific for subunit F of prostatic binding protein, the major secretory glycoprotein of the rat ventral prostate, has been determined. Its structure was established using the manual Edman degradation on the intact protein and on the most relevant fragments isolated from trypsin, chymotrypsin, thermolysin and Staphylococcus aureus protease digests of the 14C-labelled S-carboxamidomethylated component C1. Component C1 contains 88 amino acids corresponding to a molecular weight of 10246. It is an acidic polypeptide due to the presence of 17 acidic residues; its three cysteine residues are almost symmetrically distributed over the peptide chain. Highly polar regions are found in positions 17-27 and 37-47, while the C-terminal part of the molecule contains two hydrophobic segments.

Amino Acid Sequence↗
PubMed1981

Structural studies on rat prostatic binding protein. The primary structure of its glycosylated component C3.

The amino acid sequence of the glycosylated component C3 of rat prostatic binding protein has been determined. The peptides obtained by digestion of the S-carboxamidomethylated or S-aminoethylated glycoprotein with trypsin and Staphylococcus aureus protease were sequenced by manual Edman degradation. The alignment of the fragments was further established with overlapping peptides obtained by enzymic hydrolysis of the modified protein with chymotrypsin and thermolysin, and by chemical cleavage with cyanogen bromide. The glycopeptide C3 contains 77 amino acids corresponding to a molecular weight of 8653. the oligosaccharide chain is attached to the peptide by an N-glycosidic bond to asparagine-17. C3 is an acidic polypeptide due to the presence of ten acidic residues; its three cysteine residues are located at both extremities and in the middle of the molecule.

Amino Acid Sequence↗
PubMed1979

The wheat germ cell-free system possesses processing activity for the precursor of human placental lactogen.

1. Total RNA was extracted from human term placenta and mRNA purified by chromatography on oligo(dT)-cellulose. The poly(A)-containing fraction stimulated amino acid incorporation 5- to 10-fold in the wheat germ cell-free system. Immunoprecipitation with an anti-lactogen serum indicated that 14-27% of the peptides synthesized in vitro contained antigenic determinants of this hormone. 2. Analysis of the [3H]leucine labelled product in the immunoprecipitate on sodium dodecyl sulfate-polyacrylamide gels revealed a complex mixture of polypeptides. Two heavily labelled bands (I and III) were seen corresponding in mobility with pre-lactogen (Mr = 25 000) and native lactogen (Mr = 22 200), each accounting for about 30% of the immunoprecipitable radioactivity. Two additional bands with an intermediate mobility were also observed. 3. Synthesis of the hormone was inhibited by 7-methylguanosine-5'-monophosphate suggesting the presence of a 7-methylguanosine 'cap' on the 5'-end of the mRNA for lactogen. 4. Peptide analysis of the cyanogen bromide cleavage products of band I, band III and authentic lactogen showed marked similarities in their primary structure. The precursor molecule, however, was lacking the N-terminal peptide present in authentic hormone indicating the presence of an extension of 25 amino acids at this side of the molecule. 5. The presence of one or several processing enzymes in the wheat germ cell-free system was indicated by the effect of Triton X-100. Low concentrations of this detergent (0.04%) while inhibiting the protein synthesizing activity for only 15%, completely abolished the precursor cleavage activity. Under these conditions only pre-lactogen was detected in the immunoprecipitate.

Female↗
PubMed1979

Translation of biologically active messenger RNA from human placenta in Xenopus oocytes.

Polysomal RNA was extracted from human term placenta and total poly(A)-containing RNA purified by affinity chromatography on oligo(dT)-cellulose. Poly(A)-containing RNA constituted approximately 1.2% of the total polysomal RNA and 8% of this purified preparation was able to anneal with [3H]poly(U). When injected into Xenopus oocytes, this poly(A)-rich RNA directed the synthesis of a polypeptide which is immunoprecipitable with a specific antiserum to human placental lactogen. The identity of authentic human placental lactogen and the immunoreactive polypeptide synthesized in the oocytes is suggested by their identical behaviour in dodecylsulfate gel electrophoresis and by the formation of identical cyanogen bromide peptides. No precursor of human placental lactogen can be detected in the oocytes. The messenger RNA for human placental lactogen is very stable in oocytes; it is translated efficiently for a period of at least 7 days.

Animals↗
PubMed1978

Purification and characterisation of prostatic binding protein and its subunits.

The prostatic binding protein, previously described in rat ventral prostate, was isolated. The purified protein binds pregnenolone with an affinity of 1.2 X 10(6) M-1 and contains an average of 0.84 binding site per molecular. Its carbohydrate content is 3.2%. Its Mr, estimated by gel filtration, is 51 000 but in the presence of 6 M guanidine hydrochloride or 0.1% dodecylsulfate it dissociates into two subunits (S and F), which can be separated by polyacrylamide gel electrophoresis or by chromatography on hydroxyapatite. The Mr of these subunits is about 17 000, when estimated by gel filtration in 6 M guanidine hydrochloride, or 19 000 for subunit F and 20 000 for subunit S, when measured by dodecylsulfate/polyacrylamide gel electrophoresis. Their isoelectric points, estimated by isoelectric focusing in 8 M urea, are 4.6 for subunit F and 4.9 for subunit S. Prostatic binding protein and both subunits have a very similar amino acid composition. Upon reduction of disulfide bridges each subunit dissociates further into two components: one of these components is the same in both subunits.

Amino Acids↗
PubMed1977

The complete amino acid sequence of protein S16 from Escherichia coli.

This paper presents the experimental details which led to the elucidation of the complete primary structure of S16, a protein which belongs to the small subunit of E. coli ribosomes. Protein S16 was digested with trypsin, alpha-chymotrypsin, and the staphylococcal protease. The resulting peptides were purified on paper and their amino acid composition and sequence were determined. Automatic Edman degradation with a modified sequenator on the complete protein yielded information from the 56N-terminal residues. The combination of all these results led to the following complete amino acid sequence: Met-Val-Thr-Ile-Arg-Leu-Ala-Arg-His-Gly-Ala-Lys-Lys-Arg-Pro-Phe-Tyr-Gln-Val-Val-Val-Ala-Asp-Ser-Arg--Asn-Ala-Arg-Asn-Gly-Arg-Phe-Ile-Glu-Arg-Val-Gly-Phe-Phe-Asn-Pro-Ile-Ala-Ser-Glu-Lys-Glu-Glu-Gly-Thr-Arg-Leu-Asp-Leu-Asp-Arg-Ile-Ala-His-Trp-Val-Gly-Gln-Gly-Ala-Thr-Ile-Ser-Asp-Arg-Val-Ala-Ala-Leu-Ile-Lys-Glu-Val-Asn-Lys-Ala-Ala. The molecular weight derived from the sequence amounts to 9 162.

Amino Acid Sequence↗
PubMed1976

The purification and characterisation of the human-serum binding protein for the 25-hydroxycholecalciferol (transcalciferin). Identity with group-specific component.

The binding protein for 25-hydroxyvitamin D3 has been isolated from human serum by monitoring the recovery of 3H-labeled 25-hydroxyvitamin D3. After a 500-fold purification a pure protein was obtained as judged from the constant specific activity (ratio of absorbance versus radioactivity) on agarose and DEAE-Sephadex chromatography and on the presence of a single band on both cellulose acetate and polyacrylamide gel electrophoresis. The molecular weight of the purified protein was measured by gel filtration on agarose (56000), Sephadex G-75 (58000) and dodecylsulfate-polyacrylamide gel electrophoresis (56000). On sucrose gradient ultracentrifugation a sedimentation coefficient of 4.1 S was found. The isoelectric point was 4.89 S on isoelectric focusing. The stability of the protein at 60 degrees C was enhanced by the presence of excess 25-hydroxyvitamin D3. On tandem crossed immunoelectrophoresis the purified binding protein was found to be identical to the one present in whole serum. The activity of the isolated protein was demonstrated by a Ka at 4 degrees C of 1.2 X 10(10) l-mol-1. A binding capacity of 0.8 binding site/molecule was measured on a Sephadex G-25 column. During immunological studies with this protein it became evident that the binding protein is identical with another serum protein known as group-specific component (Gc). In analogy to other serum binding proteins we propose to call this group-specific component/25-hydroxyvitamin-D3-binding protein transcalciferin.

Amino Acids↗