Abbreviations: ACC: 1-Amino-cyclopropane-1-carboxylic acid ADC: arginine decarboxylase AgNO3: silver nitrate AVG: aminoethoxyvinylglycine BA: 6-benzylaminopurine DFMA: α-DL-difluromethyl arginine DFMO: α-DL-difluromethyl ornithine IAA: indole acetic acid NAA: α-naphthalene acetic acid ODC: ornithine decarboxylase PA: polyamine Put: putrescine SAM: S-adenosyl-Lmethionine STS: silver thiosulphate...

Neither n-ornithine nor n-citrulline has yet been described.’ A preparation of n-arginine by the action of arginase on racemic arginine was reported by Riesser in 1906 (2). For the ready preparation of these isomers, it was considered simplest to resolve DL-ornithine and to synthesize n-citrulline and n-arginine from n-ornithine by available procedures. The resolution of racemic ornithine was e...

Starvation of the polyamine-dependent Chinese-hamster ovary cells for ornithine or ornithine-derived polyamines in serum-free culture resulted in the formation of cadaverine and its aminopropyl derivatives, N-(3-aminopropyl)cadaverine and NN'-bis(3-aminopropyl)cadaverine. The synthesis of these unusual amines was inhibited by treatment of the cells with DL-2-difluoromethylornithine, a specific ...

We describe a systematic examination of ornithine decarboxylase activity in 120 colonic mucosal samples which were obtained from 20 subjects without colonic disease to establish the normal mean and standard deviation from proximal to distal colon. Ornithine decarboxylase activity was determined by releasing CO2 from DL-[1-14C]ornithine. The mean ornithine decarboxylase levels (CO2 liberated) ra...

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...

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...

The minimum requirements for eliciting or enhancing ornithine decarboxylase activity (EC. 4.1.1.17); L-ornithine carboxylase) in neuroblastoma cells incubated in salts-glucose solutions have been investigated. These incubation conditions permit the study of changes in ornithine decarboxylase activity independently of the growth-associated reactions that occur in cell culture media (Chen, K.Y. a...