A practicable variant of the ion exchange method for the radiometric estimation of ornithine decarboxylase activity

A known ornithine decarboxylase assay working with ion exchange separation of [3H]ornithine and [3H]putrescine has been revised. The assay can be performed in disposable 1.5 ml vessels with a total of four pipetting steps. The separation of enzyme substrate and product, respectively, requires 3 h per 50 samples. The detection limit is about 50 pmoles [3H]putrescine formed.     

Kinetic arguments for the existence of a single form of intestinal ornithine decarboxylase during the postnatal development of normal and sparse-fur mutant mice and after EGF treatment

Summary The K_m for ornithine is remarkably constant during the course of postnatal development in both normal and spf mutant mice even if a large but transient increase in ornithine decarboxylase (ODC) activity is noted. Four hours after EGF injection (4 g/g b.wt) to 17-day-old normal and spf mice, a marked stimulation of ODC activity is observed but K_m remains unaffected. These data argue against the existence of multiple forms of ODC in the intestinal mucosa of mice.Supported by grant MA-8923 from the Medical Research Council of Canada. The author is Chercheur-boursier du Fonds de la Recherche en Santé du Québec.