Urea amidolyase

Syrett, P. J., and Al-Houty, F. A. A. (1984). The phylogenetic significance ofthe occurence of urease/urea amidolyase and glycoUate oxidase/glycoUate dehydrogenase in green al e. Brit.J. Phycol. 19, 11—21. 

Urease (ATP-hydrolysing). Urea carboxylase (hydrolysing), ATP—urea amidolyase. Urea amido-lyase. 

LEFTLEY J.W. and SYRETT P.J. 1973. Urease and ATP Urea amidolyase unicellular algae. Journal of General Microbiology, 77... 

A leaf urease has been described in extracts from nodulated Glycine max grown on nitrogen-free medium, hence dependent on ureides for nitrogen nutrition (Kerr et al., 1983). This enzyme was characterized as a true urease rather than urea dehydrogenase or urea amidolyase, and differed from the seed enzyme in several aspects The seed enzyme has a broad pH optimum from 5 to above 9, while the leaf enzyme has a bimodal pH dependence with sharp optima at 5.25 and 8.75. The for urea for the leaf enzyme was about 1 xaM,... 

These convincing data showed that the I -N-ureido position of biotin serves as the site for carboxyl transfer with biotin enzymes. Lane also correctly pointed out that N O carboxyl migration might have preceded the participation of carboxybiotin in the enzymatic process. However, the well-established thermodynamic and kinetic stabilities of iV-acyl and JV-carboxy-2-imidazolidone derivatives render this possibility unlikely. Moreover, the urea carboxylase component of ATP-amidolyase, also a biotin-dependent enzyme, reversibly carboxylates urea to form iV-carboxyurea, a known example of carboxylation at the N-ureido position (333). 

---