Catalytic irreversible inhibition of bacterial and plant arginine decarboxylase activities by novel substrate and product analogues

Abstract

Arginine decarboxylase (ADC) activity from Escherichia coli and two plant species (oats and barley) was inhibited by five new substrate (arginine) and product (agmatine) analogues. The five compounds, (E)-alpha-monofluoromethyldehydroarginine (delta-MFMA), alpha-monofluoromethylarginine (MFMA), alpha-monofluoromethylagatine (FMA), alpha-ethynylagmatine (EA) and alpha-allenylagmatine (AA), were all more potent inhibitors of ADC activity than was alpha-difluoromethylarginine (DFMA), the only irreversible inhibitor of this enzyme described previously. The inhibition caused by the five compounds was apparently enzyme-activated and irreversible, since the loss of enzyme activity followed pseudo-first-order kinetics, was time-dependent, the natural substrate of ADC (arginine) blocked the effects of the inhibitors, and the inhibition remained after chromatography of inhibited ADC on Sephadex G-25 or on overnight dialysis of the enzyme. DFMA, FMA, delta-MFMA and MFMA were effective at very low concentrations (10 nM-10 microM) at inhibiting ADC activity in growing E. coli. FMA was also shown to deplete putrescine effectively in E. coli, particularly when combined with an inhibitor of ornithine decarboxylase, alpha-monofluoromethyl-putrescine. The potential uses of the compounds for the study of the role of polyamine biosynthesis in bacteria and plants is discussed.

Reconstitution of a bacterial/plant polyamine biosynthesis pathway in Saccharomyces cerevisiae

“…In addition poADC/pbAUH-transformed cells were incubated for 30 min with 100 pM of either DFMA or DL-CCdifluoromethylornithine (DFMO) , and then assayed for ADC activity. The results demonstrate that DFMO has no effect upon '*CO, released from arginine, whereas DFMA inhibits "CO, released by 86% (not shown), which is similar to the results obtained by Bitonti et al (1987), who found that 100 pM DFMA caused 75% inhibition of oat ADC. Kinetic analysis of DFMA inhibition of ADC activity showed that inhibition was time-dependent (Fig.…”

“…2b). These values are comparable to those determined for the oat ADC (Bitonti et al, 1987). Table 2.…”

Metabolic fate of L-arginine in relation to microbiostatic capability of murine macrophages.

“…The inhibitor of L-arginine decarboxylase, alpha-difluoromethylarginine (DFMA) (27) inhibited both labeled carbon dioxide production (Table II) and nitrite production (by 73%) when L-arginine was the substrate. Inhibition ofnitrite production occurred only at a high concentration (50 mM), which produced some toxicity to CM after 24 h incubation.…”

Occurrence of Agmatine Pathway for Putrescine Synthesis inSelenomonas ruminatium

“…It is also of interest that S. ruminantium ADC activity was not inhibited by putrescine, spermidine, agmatine, or -hydroxy--guanidovaleric acid, which are known to be strong inhibitors of the other ADCs shown in Table 2. 23,24) A comparison of the fold type of S. ruminantium ADC and others is discussed below.…”