Purification and some properties of rat intestinal ornithine decarboxylase |
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Authors: | K Miyamoto T Oka T Fujii M Yamaji H Minami Y Nakabou H Hagihira |
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Affiliation: | Department of Nutrition, School of Medicine, Tokushima University. |
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Abstract: | Ornithine decarboxylase (ODC) was induced in rat small intestine by treatment with hypotonic solution in vitro and purified by two procedures, a conventional procedure and an immunoaffinity procedure. SDS-polyacrylamide gel electrophoresis showed that the molecular weight of the preparation purified by the immunoaffinity procedure (Mr = 53,000) was slightly larger than that of the preparation obtained by the conventional procedure (Mr = 52,000). Values for the Km for L-ornithine (0.1 mM), the isoelectric point (5.4), and the final specific activity (5.1-5.5 x 10(5) nmol CO2/mg protein/30 min) of the two preparations were similar to those reported for the rat liver ODC. Addition of a protease inhibitor (limabean trypsin inhibitor) to the crude extract prevented the appearance of the smaller enzyme (Mr = 52,000) obtained by the conventional purification procedure. Our result indicates that the large enzyme is native ODC and the smaller one is a partial proteolysis product of native ODC. |
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