Thermostable N-carbamoyl-D-amino acid amidohydrolase: screening, purification and characterization.
A thermostable N-carbamoyl-D-amino acid amidohydrolase was found in the cells of newly isolated bacterium. Blastobacter sp. A17p-4. The bacterium also showed D-specific hydantoinase activity. The N-carbamoyl-D-amino acid amidohydrolase activity of the cells exhibited a temperature 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 120,000 and consists of three identical subunits with a relative molecular weight of about 40,000. 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 pyrimidine degradation, namely amide-ring opening enzyme, dihydropyrimidinase, and N-carbamoylamide hydrolyzing enzyme, beta-ureidopropionase. However, the purified enzyme did not hydrolyze beta-ureidopropionate; suggesting that the N-carbamoyl-D-amino acid amidohydrolase coexisting with D-specific hydantoinase, probably dihydropyrimidinase, in Blastobacter sp. A17p-4 is different from beta-ureidopropionase.
Ogawa
J
J
Department of Agricultural Chemistry, Kyoto University, Japan.
Chung
M C
MC
Hida
S
S
Yamada
H
H
Shimizu
S
S
D000581:Amidohydrolases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006090:Gram-Negative Bacteria / Q000201:enzymology*; D006358:Hot Temperature; D008969:Molecular Sequence Data
D000581:Amidohydrolases; C080477:N-carbamoyl-D-amino acid amidohydrolase