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URN: urn:nbn:de:kobv:517-opus-45875
URL: http://opus.kobv.de/ubp/volltexte/2010/4587/

Püschel, Gerhard ; Mentlein, Rolf ; Heymann, Eberhard

Isolation and characterization of Dipeptidyl Peptidase IV from human placenta

Dokument 1.pdf (1.067 KB) (SHA-1:2fbd693ec5fdb4972f3900363857f17269572132)

Kurzfassung in Englisch

Human placenta is surprisingly rich in post-proline dipeptidyl peptidase activity. Among various cell fractions, microsomes have the highest specific activity. A homogeneous enzyme preparation is obtained in a six-step purification procedure. The final preparation appears homogeneous upon dodecyl sulfate electrophoresis, but analytical isoelectric focussing reveals various active bands with isoelectric points in the range of pH 3 - 4. The enzyme is a glycoprotein containing about 30% carbohydrate. Treatment with neuraminidase lowers the isoelectric points but does not reduce the heterogeneity of the band pattern. The subunit molecular weight is 120000 as estimated by dodecyl sulfate electrophoresis, whereas Mr of the native enzyme is > 200000, as can be concluded from gel filtration experiments.
The purified dipeptidyl peptidase cleaves various synthetic and natural peptides, including substance P, kentsin, casomorphin and a synthetic renin inhibitor. In general, the specificity of the placenta peptidase is similar to that of post-proline dipeptidyl peptidase from other sources. Phenylalanylprolyl-P-naphthylamide (Km = 0.02 mM, I/ = 92 Ujmg) is the best substrate among various synthetic peptide derivatives. Only peptides with a free N-terminal amino group and proline, hydroxyproline, or alanine in position 2 of the N-terminal sequence are cieaved. However, X-Pro-Pro- . . . structures, e. g. as in bradykinin, are not attacked.
1 mM bis-(6nitrophenyI)phosphate or 1 mM diisopropylfluorophosphate completely inactivate the peptidase within 30 min at 30°C (pH 8). The peptidase is also completely inhibited by 1 mM Zn²⁺ and by other heavy metals.

Institut: Institut für Ernährungswissenschaft
DDC-Sachgruppe: Biowissenschaften, Biologie
Dokumentart: c Postprint
Schriftenreihe: Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe, ISSN 1866-8372
Bandnummer: paper 114
Quelle: European Journal of Biochemistry 126 (1982), 2, p. 359-365, DOI 10.1111/j.1432-1033.1982.tb06788.x, ISSN 0014-2956
Sprache: Englisch
Erstellungsjahr: 1982
Publikationsdatum: 04.08.2010
first published in:
FEBS Journal - 126 (1982), 2, p. 359-365
ISSN: 0014-2956
doi: 10.1111/j.1432-1033.1982.tb06788.x
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