Alternative pathways utilize or circumvent putrescine for biosynthesis of putrescine-containing rhizoferrin

Multiple pathways of putrescine biosynthesis in Escherichia coli.

The biosynthesis of spermidine and spermine from putrescine and methionine.

Putrescine, NHz(CH&NHZ, spermidine, NHz(CH&NH(CH&NHt, and sperminc, NH2(CH&NH(CH&NH(CH&NHt, are naturally occurring polyamines (for bibliography see ref. 6). That they have physiological significance is suggested by the following: they have been shown to be essential growth factors for Hemophilus injluenza (7-9) and for a mutant of Aspergillus nidulam (lo), and to stimulate the growth of Lactob...

Urea production and putrescine biosynthesis by Escherichia coli.

Cultures of Escherichia coli B and K-12 produce urea during growth in minimal medium. Results of isotopic labeling experiments were consistent with the sole source of urea being from the conversion of arginine to putrescine. Since E. coli itself has no demonstrable urease activity, the rate of urea production is a measure of the flux through the arginine to putrescine pathway.

Putrescine, Spermidine, and Spermine

Putrescine was first isolated from putrifying meat and was thought of as a decomposition product; spermine was named from its occurrence in semen. These polyamines, however, are now known to have important roles in cell growth and differentiation. Their physiological significance can be studied by analyzing the consequences of depletion of the cellular polyamine content. The results include arr...

Putrescine uptake in saintpaulia petals.

Putrescine uptake and the kinetics of this uptake were studied in petals of Saintpaulia ionantha Wendl. Uptake experiments of [(3)H] or [(14)C] putrescine were done on single petals at room temperature at various pH values. The results show that putrescine uptake occurs against a concentration gradient at low external putrescine concentration (0.5-100 micromolar) and follows a concentration gra...