A novel zinc-dependent D-serine dehydratase from Saccharomyces cerevisiae.
YGL196W of Saccharomyces cerevisiae encodes a putative protein that is unidentified but is predicted to have a motif similar to that of the N-terminal domain of the bacterial alanine racemase. In the present study we found that YGL196W encodes a novel D-serine dehydratase, which belongs to a different protein family from that of the known bacterial enzyme. The yeast D-serine dehydratase purified from recombinant Escherichia coli cells depends on pyridoxal 5'-phosphate and zinc, and catalyses the conversion of D-serine into pyruvate and ammonia with the K(m) and k(cat) values of 0.39 mM and 13.1 s(-1) respectively. D-Threonine and beta-Cl-D-alanine also serve as substrates with catalytic efficiencies which are approx. 3 and 2% of D-serine respectively. L-Serine, L-threonine and beta-Cl-L-alanine are inert as substrates. Atomic absorption analysis revealed that the enzyme contains one zinc atom per enzyme monomer. The enzyme activities toward D-serine and D-threonine were decreased by EDTA treatment and recovered by the addition of Zn2+. Little recovery was observed with Mg2+, Mn2+, Ca2+, Ni2+, Cu2+, K+ or Na+. In contrast, the activity towards beta-Cl-D-alanine was retained after EDTA treatment. These results suggest that zinc is involved in the elimination of the hydroxy group of D-serine and D-threonine. D-Serine dehydratase of S. cerevisiae is probably the first example of a eukaryotic D-serine dehydratase and that of a specifically zinc-dependent pyridoxal enzyme as well.
Ito
Tomokazu
T
Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Aichi, Japan.
Hemmi
Hisashi
H
Kataoka
Kunishige
K
Mukai
Yukio
Y
Yoshimura
Tohru
T
D000595:Amino Acid Sequence; D004492:Edetic Acid / Q000494:pharmacology; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics; D006836:Hydro-Lyases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D007700:Kinetics; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature; D015032:Zinc / Q000494:pharmacology*
D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D004492:Edetic Acid; D006836:Hydro-Lyases; C101950:D-serine dehydratase; D015032:Zinc