concentrated enzyme extracts with higher specific activities. By performing the assay in the presence of various concentrations of ornithine, we confirmed that AGAT is inhibited by ornithine, as reported previously (7 ). This observation may be of clinical interest in conditions of hyperornithinemia. Decreased brain creatine has been observed in patients affected with gyrate atrophy of the chor...

A biphasic increase of putrescine concentration occurs in rat hepatoma tissue culture cells induced to proliferate. DL-alpha-Methyl ornithine, a competitive inhibitor of ornithine decarboxylase ( L-ornithine carboxylyase, EC 4.1.1.7) of hepatoma tissue culture cells, blocks the usual increases of putrescine and spermidine concentrations in these cells, and causes a rapid fall in the levels of p...

BACKGROUND In this study, it was aimed to investigate the relationship between diabetes and breast cancer and the detection of enzymes and ornithine levels in polyamine synthesis pathway in diabetes, breast cancer and diabetic breast cancer patients. METHODS Ornithine, arginine decarboxylase, ornithine decarboxylase and agmatinase levels have been measured in serum of all groups. Ornithine le...

Most mitochondrial proteins are encoded in the nucleus and translated in the cytoplasm as larger precursors containing NH2-terminal "leader" peptides, which are strikingly basic in overall amino acid composition. Recent experiments indicate that these leader peptides are both necessary and sufficient to direct post-translational recognition and import of precursors by mitochondria. In this repo...

DL-alpha-Difluoromethylornithine, an enzyme-activated irreversible inhibitor of eukaryotic ornithine decarboxylase and consequently of putrescine biosynthesis, inhibited ornithine decarboxylase in enzyme extracts from Pseudomonas aeruginosa in a time-dependent manner t1/2 1 min, and also effectively blocked the enzyme activity in situ in the cell. Difluoromethylornithine, however, had no effect...

Intraventricular administration of nanogram quantities of nerve growth factor to adult rats results in a marked increase in the activity of ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) in the brain. The increase occurs in all major brain regions and the activity is maximal by 7.5 hr after administration. The enzyme response to nerve growth factor increases in magnitude durin...

A transient increase in ornithine decarboxylase activity and polyamine biosynthesis occurs in the intestinal mucosa of the newborn rat in the third week after birth. During this period, there is a rapid conversion of the mucosa from a fetal to a mature adult status. A similar increase in ornithine decarboxylase activity also accompanies the rapid recovery of the mucosa 1 week after an injury is...

PathoTec strips and spot biochemical tests were evaluated for the ability to biotype Haemophilus influenzae and Haemophilus parainfluenzae. Indole, urease, and ornithine decarboxylase reactions were tested. The results of PathoTec strips compared favorably with those conventional methods; the percent agreements were as follows: indole, 100; urease, 99.5; and ornithine, 97.5. Spot tests were sim...

The renal basic amino acid metabolism often differs in rodents, strict carnivores, and omnivore species. Given the pivotal role of L-arginine and L-ornithine in several metabolic pathways and the fact that the dog is closely related to humans, being also an omnivore, we tested whether L-arginine metabolism and L-ornithine catabolism take place in the dog kidney. We examined the metabolism of L-...

Ornithine decarboxylase (ODC) activity of Ehrlich carcinoma cells was increased more than 36-fold after being maintained for 3.5 hr in vitro in a special chamber which allowed continuous perifusion with 0.5 mM ornithine; if incubated in vitro without perifusion the ODC activity was, of course, only 9-fold by the same concentration of ornithine. Ornithine withdrawal from the perifusion medium re...