Hydroxylamine Analogue of Agmatine: Magic Bullet for Arginine Decarboxylase

Abstract

The biogenic polyamines, spermine, spermidine (Spd) and putrescine (Put) are present at micro-millimolar concentrations in eukaryotic and prokaryotic cells (many prokaryotes have no spermine), participating in the regulation of cellular proliferation and differentiation. In mammalian cells Put is formed exclusively from L-ornithine by ornithine decarboxylase (ODC) and many potent ODC inhibitors are known. In bacteria, plants, and fungi Put is synthesized also from agmatine, which is formed from L-arginine by arginine decarboxylase (ADC). Here we demonstrate that the isosteric hydroxylamine analogue of agmatine (AO-Agm) is a new and very potent (IC50 3•10−8 M) inhibitor of E. coli ADC. It was almost two orders of magnitude less potent towards E. coli ODC. AO-Agm decreased polyamine pools and inhibited the growth of DU145 prostate cancer cells only at high concentration (1 mM). Growth inhibitory analysis of the Acremonium chrysogenum demonstrated that the wild type (WT) strain synthesized Put only from L-ornithine, while the cephalosporin C high-yielding strain, in which the polyamine pool is increased, could use both ODC and ADC to produce Put. Thus, AO-Agm is an important addition to the set of existing inhibitors of the enzymes of polyamine biosynthesis, and an important instrument for investigating polyamine biochemistry.

Random Mutagenesis of Filamentous Fungi Strains for High-Yield Production of Secondary Metabolites: The Role of Polyamines

“…However, along with beneficial changes that increase the production of the target SM, reduce the amount of spin-off products, and others, numerous side changes begin to accumulate in the fungal strain. They can appear in a slow growth on agar and liquid media [27,64,65], a decrease in stress resistance [66], reduction in the conidia formation [64] and many other properties, expressed in a decrease in the overall viability of the strain [66,67]. Finally, the stage comes when the next mutagenic effect no longer leads to further strain improvement.…”

“…Adapted with permission from [44]. of ODC, the key enzyme of PAs biosynthesis, on minimal agar media [65]. The addition of 5 mM α-difluoromethylornithine (DFMO) or 5 mM of 1-aminooxy-3-aminopropane (APA) completely inhibited the growth of the WT strain, unlike HY strain (Figure 4) [65].…”

“…of ODC, the key enzyme of PAs biosynthesis, on minimal agar media [65]. The addition of 5 mM α-difluoromethylornithine (DFMO) or 5 mM of 1-aminooxy-3-aminopropane (APA) completely inhibited the growth of the WT strain, unlike HY strain (Figure 4) [65]. Such kind of resistance against inhibiters of key enzyme for PAs production turned out to be rather strange since HY strain is significantly weakened after SCI program [32,61,64,66,67].…”

“…The inhibitory analysis demonstrated shift from the ADC-dependent to ODC-dependent biosynthesis of Put. During the fermentation for CPC production the total PAs content into HY strain has been increased by about fivefold [65].…”

“…The reasons for the increased production of PAs in the HY strain were discussed [65]. One on the reasons may be related to strain improvement techniques.…”