Occurrence of free D-amino acids and aspartate racemases in hyperthermophilic archaea.
The occurrence of free D-amino acids and aspartate racemases in several hyperthermophilic archaea was investigated. Aspartic acid in all the hyperthermophilic archaea was highly racemized. The ratio of D-aspartic acid to total aspartic acid was in the range of 43.0 to 49.1%. The crude extracts of the hyperthermophiles exhibited aspartate racemase activity at 70 degrees C, and aspartate racemase homologous genes in them were identified by PCR. D-Enantiomers of other amino acids (alanine, leucine, phenylalanine, and lysine) in Thermococcus strains were also detected. Some of them might be by-products of aspartate racemase. It is proven that D-amino acids are produced in some hyperthermophilic archaea, although their function is unknown.
Matsumoto
M
M
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
Homma
H
H
Long
Z
Z
Imai
K
K
Iida
T
T
Maruyama
T
T
Aikawa
Y
Y
Endo
I
I
Yohda
M
M
D000591:Amino Acid Isomerases / Q000235:genetics / Q000302:isolation & purification*; D000596:Amino Acids / Q000737:chemistry*; D001105:Archaea / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D001224:Aspartic Acid / Q000737:chemistry*; D019620:Desulfurococcaceae / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D006358:Hot Temperature; D008969:Molecular Sequence Data; D019711:Pyrococcus / Q000737:chemistry / Q000201:enzymology / Q000235:genetics; D013237:Stereoisomerism; D019712:Thermococcus / Q000737:chemistry / Q000201:enzymology / Q000235:genetics
D000596:Amino Acids; D001224:Aspartic Acid; D000591:Amino Acid Isomerases; C019749:aspartate racemase