Structure and Properties of the Putrescine Carbamoyltransferase of Streptococcus faecalis

Abstract

Ornithine and putrescine carbamoyltransferases from Streptococcus faecalis ATCC11700 have been purified and their structural properties compared. The molecular weight of native ornithine carbamoyltransferase, measured by molecular sieving, is 250 000. It is composed of six apparently identical subunits with a molecular weight of 39 000, as determined by cross-linking with the bifunctional reagent glutaraldehyde followed by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate. Using the same method, putrescine carbamoyltransferase is a trimer of 140 000 consisting of three identical subunits with a molecular weight of 40 000. Ornithine carbamoyltransferase displays a narrow specificity towards its substrate, ornithine. In contrast, putrescine carbamoyltransferase carbamoylates ornithine and several diamines (diaminopropane, diaminohexane, spermine, spermidine, cadaverine) in addition to its preferred substrate, putrescine, but with a considerable lower efficiency than for putrescine. The kinetic mechanism of putrescine carbamoyltransferase has been investigated. Initial velocity studies yield intersecting plots using either putrescine or ornithine as substrate, indicating a sequential mechanism. The patterns of protection of the enzyme by the reactants during heat inactivation as well as the results of product and dead-end inhibition studies provide evidence for a random addition of the substrates. The putrescine inhibition that is induced by phosphate does, however, suggest that a preferred pathway exists in which carbamoylphosphate is the leading substrate. The different kinetic constants have been established. The properties of putrescine carbamoyltransferase are compared to the known properties of other carbamoyltransferases. The evolutionary implications of this comparison are discussed.

Lmo0036, an ornithine and putrescine carbamoyltransferase in Listeria monocytogenes, participates in arginine deiminase and agmatine deiminase pathways and mediates acid tolerance

“…Second, in contrast with OTC being substrate-specific, PTC utilizes a wide range of substrates other than putrescine, including ornithine and several diamines (diaminopropane, diaminohexane, spermine, spermidine, cadaverine). However, specific activities of PTC using these alternative substrates are apparently lower (Wargnies et al, 1979).…”

“…At least two differences are found between these two carbamoyltransferases. First, PTC possesses both anabolic and catabolic activities in most cases (Wargnies et al, 1979) (Fig. 1d).…”

“…1c) (Legrain & Stalon, 1976), cPTC catalyses the decarbamoylation reaction of carbamoylputrescine (the deimination product of agmatine) producing carbamoylphosphate and putrescine ( Fig. 1d) (Wargnies et al, 1979). However, little is known about the function of Lmo0036, the putative carbamoyltransferase in L. monocytogenes.…”

Diguanidinobutane (Arcaine) Degradation inRhodococcussp. C-x

“…i) The deiminase and the amidase were most active toward agmatine and carbamoylputrescine, respectively, ii) agmatine deiminase and carbamoylputrescine amidase have been found in cells of fluorescent Pseudomonas, [6][7][8][9] A. globiformis,12) and B. helvolum 12 ) grown on agmatine, and iii) no phosphate was required for the breakdown of the carbamoylputrescine (data not shown), unlike putrescine carbamoyltransferase, which catalyzes the phosphorolytic breakdown of carbamoylputrescine in Streptococcus faecalis. 24,25) …”

Comparative studies on the degradation of guanidino and ureido compounds by Pseudomonas

“…The same diversity appears in the degradation of ureido compounds : ureohydrolysis is observed for allantoic acid and ureidoglycine; hydrolysis of the ureido group to C 0 2 and ammonia occurs for carbamoylputrescine (Mercenier et al, 1980 ;Stalon & Mercenier, 1984), carbamoylalanine (Carvaca & Grisolia, 1958 ;Campbell, 1960) and carbamoylsarcosine (Kim et al, 1976;Shimizu et al, 1986); phosphorolysis is observed for citrulline in Pseudornonas of group I having the arginine deiminase pathway and in other bacterial systems for carbamoylputrescine (Wargnies et al, 1979) and carbamoyloxamate (Vander Wauven et al, 1986). …”