Enzymes arginine decarboxylase

AGM (decarboxylated arginine), an endogenous amine derived from arginine and its biosynthetic enzyme (arginine decarboxylase), is broadly distributed in the CNS, including the SDH (Li et al., 1994a Raasch et al., 1995 Reis and Regunathan,... 

Figure 22 Biosynthesis of polyamines through the arginine decarboxylase pathway. Putrescine derived from L-arginine through the action of three successive enzymes arginine decarboxylase (ADC), agmatine iminohydrolase (AIH), and N-carbamoylputrescine amidohydrolase (NCPAH).

Putrescine accumulation has been investigated in some detail and studies with radioactive precursors (see e.g.. Smith and Richards, 1%2 Smith, 1965) have established that it is synthesized from arginine (see Fig. 1). The mechanism underlying putrescine accumulation is uncertain although two of the biosynthetic enzymes, arginine decarboxylase, and iV-carbamyl pqtres-cine amidohydrolase exhibit two- to fourfold increases under conditions of K deficiency (Smith, 1%5). No increase was found to occur in the activity of agmatine iminohydrolase (Smith, 1969). 

Further modifications using the same strain of ODC S. cerevisiae reconstituted a bacterial/plant polyamine synthesis pathway in yeast [41], The ODC strain was transformed with plasmids encoding arginine decarboxylase and ag-matine ureohydrolase, which conferred polyamine-independent growth on the recombinant microbe. A similar construction could be used to screen for inhibitors of the homologous enzymes from Apicomplexan protozoa, which synthesize poly amines through this pathway [42]. 

F. (1). Tropane alkaloids biosynthetic pathway. The known enzymes are indicated. ODC (ornithine decarboxylase), ADC (arginine decarboxylase), PMT (putrescine methyl transferase), MPO (methyl putrescine oxidase), TRI, TRII (tropinone reductase I, II), H6H (hyoscyamine 6p hydroxylase). 

Pyruvoyl cofactor is derived from the posttranslational modification of an internal amino acid residue, and it does not equilibrate with exogenous pyruvate. Enzymes that possess this cofactor play an important role in the metabolism of biologically important amines from bacterial and eukaryotic sources. These enzymes include aspartate decarboxylase, arginine decarboxylase," phosphatidylserine decarboxylase, . S-adenosylmethionine decarboxylase, histidine decarboxylase, glycine reductase, and proline reductase. ... 

Certain bacterial strains, such as Pediococcus or Lactobacillus, may contain this type of enzyme. They may also be capable of biosynthesizing them by induction, in the presence of an amino acid precursor (Brink et al., 1990). Arginine is the amino acid precnrsor of several bioamines. Figure 5.9 shows that decarboxylation by bacterial arginine decarboxylase prodnces agmatine, a bioamine precnrsor of pntrescine. Ornithine (Figure 5.9) may... 

Reaction 5 is catalyzed by arginine decarboxylase which has been found in barley (Smith, 1963). Agmatine can be converted to A-carbamoyl putrescine (reaction 6) by agmatine iminohydrolase (E.C. 3.5.3.12). This enzyme has been found in extracts of maize leaves and sunflower (Smith, 1969). The further hydrolysis of A/ -carbamyl putrescine to putrescine (reaction 7) is catalyzed by A-carbamyl putrescine amidohydrolase which has been found in barley leaf extracts (Smith, 1965). The enzyme activities catalyzing reactions 5 and 7 are increased several-fold in K-deficient barley leaves (Smith, 1963, 1965) which correlates well with the high level of putrescine accumulation in K-deficient barley. Further metabolism of putrescine is discussed by Smith, this series, Vol. 7, Chapter 9. 

Pyrrolidine alkaloids are derived via the intermediacy of putrescine (1). Putrescine is derived by decarboxylation of arginine or ornithine the enzyme ornithine decarboxylase (E.C. 4.11.1.17) has been detected in tobacco roots (Leete, 1980) (also see Chapter 30). Arginine decarboxylase (E.C. 4.1.1.19) first converts arginine to agmatine, and subsequently to car-bamoylputrescine, and then to putrescine see Fig. 28.7 of Chapter 28). In several studies, arginine, rather than ornithine, appears to be the major precursor (Leete, 1990). 

Fig. 2. Biogenetic links between A primary metabolism and B the alkaloid-specific pathway. CAP, N-carbamoylputrescine GABA, 4-aminobutyric acid. Inhibitors DFMA, a-difluorome-thylarginine, HEH, /1-hydroxyethylhydrazine. Enzymes 1, arginine decarboxylase 2, agmatine iminohydrolase 3, JV-carbamoylputrescine amidohydrolase 4, diamine oxidase 5, pyrroline dehydrogenase (NAD+-dependent) 6, spermidine synthase 7, a putrescine-producing poly-amine oxidase (H H-insensitive) 8, homospermidine synthase 9, an HEH-sensitive polyamine oxidase...

Ornithine decarboxylase (ODC) and arginine decarboxylase (ADC) are the first enzymes involved in the formation of tropane alkaloids (TPAs) snch as atropine and cocaine (Fig. 3). Decarboxylation of ornithine yields pntrescine, whereas arginine is converted to agmatine, which is metabolized to putrescine via a second rente. ADC is assnmed to play the primary role in TPA synthesis [18]. 

In this context it is also of interest to point out that the clear difference between healthy and diseased trees, in their content of amines, is of special significance in the case of acid stress. An increase of polyamine biosynthesis is the result of the stimulation by the acidic environment of arginine decarboxylase (Young and Galston, 1983), the key enzyme which produces putrescine, the polyamine precursor, from arginine via agmatine. Amine biosynthesis increase is then one of the primary metabolic responses of plants to acid stress. 

Enzymes are the best catalysts known. They mediate a vast array of chemical transformations in all living organisms and do so very efficiently under mild conditions. Most enzymatic mechanisms of catalysis have ample precedents in organic catalytic reactions. Yet reactions that are very fast in the presence of enzymes, become extremely slow in their absence, and some have half-lives approaching the age of the Earth. For example, the half-hfe for the spontaneous decarboxylation of amino acids is 1100 million years, but in the presence of arginine decarboxylase, the rate constant of the catalysed reaction is in the vicinity of 100-1000 sec [1]. This, as many other enzyme-catalysed reactions, demonstrates the excellent kinetic efficiency of these catalysts. In general, enzymes produce rate enhancements that range from lO -fold to 10 -fold. 

Burrell M, Hanfrey CC, Murray EJ, Stanley-Wall NR, Michael AJ (2010) Evolution tmd multiplicity of arginine decarboxylases in polyamine biosynthesis and essential role in Bacillus subtilis biofilm formation. J Biol Chem 285 39224-39238 Burrell M, Hanfrey CC, Kinch LN, Elliott KA, Michael AJ (2012) Evolution of a novel lysine decarboxylase in siderophore biosynthesis. Mol Microbiol 86 485-499 Cacciapuoti G, Porcelli M, Moretti MA, Sorrentino F, Concilio L, Zappia V et al (2007) The first agmatine/cadaverine aminopropyl transferase biochemical and structural characterization of an enzyme involved in polyamine biosynthesis in the hyperthermophilic archaeon Pyrococcus furiosus. J Bacteriol 189 6057-6067... 

Giles TN, Graham DE (2008) Crenarchaeal arginine decarboxylase evolved from an S-adenosylmethionine decarboxylase enzyme. J Biol Chem 283 25829-25838... 

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