Biomedical subjects

W N Schwartz

Publications and source records attributed to W N Schwartz.

4 recordsLinked to original sources

PubMed1985

The comparative distribution of [Lys8-Asn9]-neurotensin8-13-like immunoreactivity in chicken and rat tissues.

The presence of [Lys8-Asn9]-neurotensin8-13-like immunoreactivity was studied by radioimmunoassay in chicken and rat tissues. In the chicken, [Lys8-Asn9]-neurotensin8-13-like immunoreactivity showed a wide distribution throughout the central nervous system and the gastrointestinal tract, and the immunoreactive material co-eluted with the synthetic peptide on reverse-phase high performance liquid chromatography. In the rat, [Lys8-Asn9]-neurotensin8-13-like immunoreactivity was widely distributed when 0.1 M HCl was used as the extraction procedure. However, the immunoreactive material did not co-elute with the synthetic peptide on reverse-phase high performance liquid chromatography; moreover, the addition of the aspartic proteinase inhibitor pepstatin to the extraction medium resulted in a large reduction in the levels of [Lys8-Asn9]-neurotensin8-13-like immunoreactivity and no immunoreactive material could be detected when the tissues were extracted using acetone/HCl. The present results therefore indicate that [Lys8-Asn9]-neurotensin8-13-like immunoreactivity is not present in rat tissues. That which was detected resulted from an extraction artefact.

Animals↗

PubMed1985

Conversion and inactivation of opioid peptides by rabbit brain endo-oligopeptidase A.

The conversion of BAM-12P to Met-enkephalin and the hydrolysis of the Phe-Met and Phe-Leu bonds of met-enkephalin-Arg-Phe and Leu-enkephalin-Arg-Arg, respectively, by rabbit brain endo-oligopeptidase A were demonstrated. Peptide fragments were isolated by high performance liquid chromatography and identified by amino acid analysis. BAM 22P was not hydrolysed by the enzyme. The concentration dependent inhibition of BAM-12P conversion into Met-enkephalin by bradykinin and vice-versa provided additional evidence that endo-oligopeptidase A cleaves both the Phe5-Ser6 bond in bradykinin and the Met5-Arg6 bond of BAM-12P.

Amino Acids↗

PubMed1980

Human cathepsin H.

Cathepsin H was purified from human liver by a method involving autolysis and acetone fractionation, and chromatography on DEAE-cellulose, Ultrogel AcA 54, hydroxyapatite and concanavalin A-Sepharose. The procedure allowed for the simultaneous isolation of cathepsin B and cathepsin D. Cathepsin H was shown to consist of a single polypeptide chain of 28 000 mol.wt., and affinity for concanavalin A-Sepharose indicated that it was a glycoprotein. The enzyme existed in multiple isoelectric forms, the two major forms having pI values of 6.0 and 6.4; it hydrolysed azocasein (pH optimum 5.5), benzoylarginine 2-naphthylamide (Ba-Arg-NNap), leucyl 2-naphthylamide (Arg-NNap), (pH optimum 6.8). Arg-NNap and Arg-NMec, unlike Bz-Arg-NNap-, were not hydrolysed by human cathepsin B. Cathepsin H was similar to cathepsin B in being irreversibly inactivated by exposure to alkaline pH. Sensitivity to chemical inhibitors by 1 microM-leupeptin, which gave essentially complete inhibition of the other lysosomal cysteine proteinases, cathepsins B and L.

Cathepsins↗

PubMed1977

Degradation of myofibrillar proteins by cathepsins B and D.

Cathepsin B and cathepsin D were purified from rat liver and skeletal muscle. Electrophoretic analyses revealed that the enzymes were highly purified, and isoelectric focusing demonstrated multiple forms of both enzymes. Purified actin and myosin, as well as actin and myosin in myofilaments and myofibrils, were degraded by the purified cathepsins B and D. Degradation of myosin was completely blocked by the cathepsin B and D inhibitors, leupeptin and pepstatin, respectively. Cathepsins B and D were visualized by electron microscopy, using CBZ-Ala- Arg-Arg-4-methoxy-beta-naphthylamine and BZ-Arg-Gly-Phe-Leu-4-methoxy-beta-naphthylamine as substrates.

Animals↗