J. Ogawa et al., THERMOSTABLE N-CARBAMOYL-D-AMINO ACID AMIDOHYDROLASE - SCREENING, PURIFICATION AND CHARACTERIZATION, Journal of biotechnology, 38(1), 1994, pp. 11-19
A thermostable N-carbamoyl-D-amino acid amidohydrolase was found in th
e cells of newly isolated bacterium, Blastobacter sp. A17p-4. The bact
erium also showed D-specific hydantoinase activity. The N-carbamoyl-D-
amino acid amidohydrolase activity of the cells exhibited a temperatur
e optimum at 50-55 degrees C, and was stable up to 50 degrees C. The N
-carbamoyl-D-amino acid amidohydrolase of Blastobacter sp. A17p-4 was
purified to homogeneity and characterized. It has a relative molecular
weight of about 120000 and consists of three identical subunits with
a relative molecular weight of about 40000. N-Carbamoyl-D-amino acids
having hydrophobic groups served as good substrates for the enzyme. It
has been suggested that D-amino acid production from DL-5-substituted
hydantoin involves the action of a series of enzymes involved in pyri
midine degradation, namely amide-ring opening enzyme, dihydropyrimidin
ase, and N-carbamoylamide hydrolyzing enzyme, beta-ureidopropionase. H
owever, the purified enzyme did not hydrolyze beta-ureidopropionate; s
uggesting that the N-carbamoyl-D-amino acid amidohydrolase coexisting
with D-specific hydantoinase, probably dihydropyrimidinase, in Blastob
acter sp. A17p-4 is different from beta-ureidopropionase.