Metabolism ofL-Arginine, Agmatine, and Related Compounds inNocardioides simplex

Abstract

Nocardioides simplex IFO 12069 (Arthrobacter simplex ATCC 6946) was examined for the degradation of L-ornithine, L-citrulline, L-arginine, D-arginine, agmatine, carbamoylputrescine, and putrescine, and the results were compared with those obtained in a previous study with A. globiformis and Brevibacterium helvolum. D-Arginine as well as L-arginine was degraded via the arginine oxygenase pathway. A part of L-citrulline was probably degraded via the pathway. The L-ornithine degradation via the pathway was obscure. Guanidinobutyrase was induced by agmatine, which was shown to be degraded via a unique pathway. The first step of the pathway converted agmatine to 4-guanidinobutyraldehyde by transferring the amino group to pyruvate. The second step was the NAD-Iinked dehydrogenation of the aldehyde to 4-guanidinobutyrate, which was then degraded to 4-aminobutyrate. The enzymes for the first and second steps were identified as diaminopropane aminotransferase (EC 2.6.1.-) and aminobutyraldehyde dehydrogenase (EC 1.2.1.19), respectively. These enzymes also degraded putrescine to 4-aminobutyrate. Carbamoylputrescine was converted by the aminotransferase to the corresponding aldehyde, which was accumulated in the medium.

Agmatine oxidation by copper amine oxidase

“…In fact, the formation of 4‐guanidinobutyraldehyde was never observed. Therefore, 4‐guanidinobutyraldehyde, the best substrate of the aldehyde dehydrogenase that occurs in Fabaceae plants and rat hepatocytes with copper amine oxidase [39–42], does not appear to originate from the enzymatic cycling of agmatine to N ‐amidino‐2‐hydroxypyrrolidine.…”

Ornithine δ-aminotransferase

“…34 There is also a significant similarity of OAT to diamine (or polyamine) aminotransferases, which have been described to act in polyamine metabolism in some bacteria. [35][36][37][38][39] It should be noted here that the diamine aminotransferase (DAT; EC 2.6.1.29) from E. coli was described in the middle 60s and that time it was the first known aminotransferase utilizing a substrate with no carboxyl group. 35 Figure 4 shows the multiple sequence alignment of several OATs from Leguminosae plants, GABA-AT from A. thaliana and DAT from E. coli.…”

“…TMP-1, 38 and Nocardioides (Arthrobacter) simplex. 39 As amino donors, the enzymes accept particularly 1,3-diaminopropane, putrescine, agmatine, spermidine and cadaverine. Pyruvate and 2-oxoglutarate were found to be amino acceptors.…”

Degradation of 2-Ketoarginine by Guanidinobutyrase in Arginine Aminotransferase Pathway ofBrevibacterium helvolum

“…We reported previously that A. globiformis,4) B. helvolum,4) and N. simplex 5 ) had both the oxygenase and aminotransferase pathways. The third step of the oxygenase pathway is the hydrolysis of 4-guanidinobutyrate to 4-aminobutyrate and urea.…”

“…1) The arginine oxygenase pathway is distributed among Streptomyces griseus 2 ) and some bacteria related phylogenetically to actinomycetes, including Arthrobacter globiformis IFO 12137 (ATCC 8010), Brevibacterium he/volum IFO 12073, and Nocardioides simplex IFO 12069 (Arthrobacter simplex A TCC 6946). [3][4][5] On the other hand, Tochikura et al 6) have reported that N. simplex has the arginine aminotransferase pathway, which degrades Larginine to 2-ketoornithine (2-keto-5-aminovalerate) via 2-ketoarginine (2-keto-5-guanidinovalerate). Although the enzyme for the first step of the pathway was identified as arginine aminotransferase, the enzyme that hydrolyzes 2-ketoarginine to 2-ketoornithine and urea has not been identified nor characterized.…”