Nanaya Tamaki
Kobe Gakuin University
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Featured researches published by Nanaya Tamaki.
Gene | 1996
Naoki Hamajima; Koichi Matsuda; Shigeko Fujimoto Sakata; Nanaya Tamaki; Makoto Sasaki; Masaru Nonaka
We have isolated cDNA clones encoding dihydropyrimidinase (DHPase) from human liver and its three homologues from human fetal brain. The deduced amino acid (aa) sequence of human DHPase showed 90% identity with that of rat DHPase, and the three homologues showed 57-59% aa identity with human DHPase, and 74-77% aa identity with each other. We tentatively termed these homologues human DHPase related protein (DRP)-1, DRP-2 and DRP-3. Human DRP-2 showed 98% aa identity with chicken CRMP-62 (collapsin response mediator protein of relative molecular mass of 62 kDa) which is involved in neuronal growth cone collapse. Human DRP-3 showed 94-100% aa identity with two partial peptide sequences of rat TOAD-64 (turned on after division, 64 kDa) which is specifically expressed in postmitotic neurons. Human DHPase and DRPs showed a lower degree of aa sequence identity with Bacillus stearothermophilus hydantoinase (39-42%) and Caenorhabditis elegans unc-33 (32-34%). Thus we describe a novel gene family which displays differential tissue distribution: i.e., human DHPase, in liver and kidney; human DRP-1, in brain; human DRP-2, ubiquitously expressed except for liver; human DRP-3, mainly in heart and skeletal muscle.
American Journal of Human Genetics | 1998
Naoki Hamajima; M Kouwaki; Peter Vreken; K Matsuda; Satoshi Sumi; M Imaeda; S Ohba; K Kidouchi; M Nonaka; M Sasaki; Nanaya Tamaki; Y Endo; R.A. de Abreu; Jan J. Rotteveel; A. B. P. van Kuilenburg; A. H. van Gennip; H Togari; Yoshiro Wada
Dihydropyrimidinase (DHP) deficiency (MIM 222748) is characterized by dihydropyrimidinuria and is associated with a variable clinical phenotype. This disease might be associated with a risk of 5-fluorouracil toxicity, although no cases have been reported. We present here both the molecular characterization of the human DHP gene and, for the first time, the mutations causing DHP deficiency. The human DHP gene spans >80 kb and consists of 10 exons. It has been assigned to 8q22, by FISH. We performed mutation analysis of genomic DNA in one symptomatic and five asymptomatic individuals presenting with dihydropyrimidinuria. We identified one frameshift mutation and five missense mutations. Two related Japanese adult subjects were homozygous for the Q334R substitution, whereas two other, unrelated Japanese infant subjects were heterozygous for the same mutation, but this mutation is not common in the Japanese population. A Caucasian pediatric patient exhibiting epileptic attacks, dysmorphic features, and severe developmental delay was homozygous for W360R. Using a eukaryotic expression system, we showed that all mutations reduced enzyme activity significantly, indicating that these are crucial DHP deficiency-causing mutations. There was no significant difference, in residual activity, between mutations observed in the symptomatic and those observed in the asymptomatic individuals.
Biochimica et Biophysica Acta | 1996
Koichi Matsuda; Shigeko Fujimoto Sakata; Masae Kaneko; Naoki Hamajima; Masaru Nonaka; Makoto Sasaki; Nanaya Tamaki
A cDNA encoding dihydropyrimidinase has been isolated from a rat cDNA library. The N-terminal and an internal amino acid sequences were determined, and PCR primers were designed based on these sequences. Using a cDNA fragment amplified by RT-PCR with these primers, three cDNA clones were isolated from a rat liver library. The clone with the longest insert of 2129 bp contained a 1557 bp open reading frame encoding a polypeptide of 519 residues with a molecular mass of 56,832 Da.
British Journal of Nutrition | 1995
Nanaya Tamaki; Shigeko Fujimoto-Sakata; Mariko Kikugawa; Masae Kaneko; Satomi Onosaka; Tatsuya Takagi
The body weight and feed intake of rats fed on a Zn-deficient diet for 28 d were reduced compared with those of control rats. The feed intakes of the Zn-deficient and control groups during the period were 10.2 (SE 0.3) and 15.7 (SE 0.2) g/d respectively. Cyclic variations in feed intake and body-weight changes were found in analysis not only of all the data for five rats but also that in each individual rat. Cosinor analysis revealed that the cyclical period of both the feed intake and body-weight change in the Zn-deficient rats was 3.5 (SE 0.1) d. The mesor and amplitude value of the feed intake in the Zn-deficient rats was 10.1 (SE 0.4) g/d and 3.5 (SE 0.5) g/d respectively, and that of body-weight change was 1.4 (SE 0.1) g/d and 7.9 (SE 1.3) g/d respectively. Among pyrimidine-catabolizing enzymes, dihydropyrimidinase (EC 3.5.2.2) activity showed significant retardation in the Zn-deficient rat liver with decrease of the enzyme protein. The ratio of apo-form to holo-form dihydropyrimidinase in the liver was not affected by the Zn-deficient diet.
Biochimica et Biophysica Acta | 1986
Shigeko Fujimoto; Naomi Mizutani; Chizuru Mizota; Nanaya Tamaki
beta-Alanine aminotransferase from rat liver was purified to electrophoretic homogeneity. The immunological and kinetic properties of this enzyme were similar to those of the enzyme from rat brain. However, the liver enzyme transaminates from beta-alanine to 2-oxoglutaric acid, while the brain enzyme transaminates from gamma-aminobutyric acid. beta-Alanine aminotransferase activity in regenerating rat liver was lower than that in control rat liver. Activity of this enzyme, as well as of other uracil-catabolizing enzymes (Weber, G., Queener, S.F. and Ferdinandus, A. (1970) in Advances in Enzyme Regulation (Weber, G., ed.), Vol. 9, pp. 63-95, Pergamon Press, Oxford), was low in newborn rat liver and increased about 5-fold, reaching the level observed in adult rat liver. beta-Alanine and prednisolone induced beta-alanine aminotransferase in rat liver.
Biochimica et Biophysica Acta | 1992
Masae Kaneko; Yasuhide Kontani; Mariko Kikugawa; Nanaya Tamaki
Among pyrimidine derivatives, we found that 5-fluorouracil;potently inhibited purified rat liver d -3-aminoisobutyrate-pyruvate aminotransferase, whereas 5-fluorouridine did so to a much lesser extent. 5-Fluorouracil acted as a competitive inhibitor against β-alanine with a K i of 56 μM, and was uncompetitive against pyruvic acid, with a K i of 73 μM. α-Fluoro-β-alanine, a metabolite of 5-fluorouracil, was also a competitive inhibitor with respect to β-alanine with a K i of 8.0 mM. 5-Fluorouracil acted also as a competitive inhibitor of 4-aminobutyrate aminotransferase with respect to β-alanine with a K i value of 1.9 mM, and was uncompetitive against 2-oxoglutaric acid, with a K i of 1.8 mM.
FEBS Letters | 1985
Nanaya Tamaki; Shigeko Fujimoto; Naomi Mizutani; Chizuru Mizota
When 6‐azauracil was subcutaneously injected, β‐aminoisobutyric acid and β‐alanine contents were increased 22 and 61‐fold, respectively, in rat liver. Incorporation of [methyl‐14Cithymine into β‐aminoisobutyric acid was increased to 42‐fold by 6‐azauracil treatment. The absolute configuration of this amino acid was proved to be the (R)‐form by means of a gas‐chromatographic technique. 6‐Azauracil inhibited β‐alanine‐pyruvate aminotransferase activity with an I 50 of approx. 2.5 mM.
Biochimica et Biophysica Acta | 1987
Nanaya Tamaki; Shigeko Fujimoto; Chizuru Mizota; Mariko Kikugawa
Abstract L -β-Aminoisobutyrate served as an amino donor for purified β-alanine-oxo-glutarate aminotransferase from rat liver when 2-oxoglutarate was employed as an amino acceptor, but he D -isomer did not. L -β-Aminoisobutyrate acted as a competitive inhibitor with respect to β-alanine and had a Ki of approximately 2.6 mM, which is the same value as the Km of 2.7 mM. When the crude extract was applied to a DEAE-Sepharose CL-6B column, L -β-aminoisobutyrate aminotransferase and β-alanine-oxo-glutarate aminotransferase activities were found in the same fractions with a single peak. Antiserum to rat liver β-alanine-oxo-glutarate aminotransferase inhibited L -β-aminoisobutyrate aminotransferase activity in rat liver in the same way as β-alanine-oxo-glutarate aminotransferase activity.
FEBS Letters | 1988
Mariko Kikugawa; Shigeko Fujimoto; Chizuru Mizota; Nanaya Tamaki
Propionic acid and isobutyric acid, which are structural analogues of N‐carbamoyl‐β‐alanine and N‐carbamoyl‐β‐aminoisobutyric acid, respectively, acted as an allosteric activator as well as a competitive inhibitor of purified rat liver β‐ureidopropionase. Propionic acid and isobutyric acid had a K i value of approx. 0.3 mM at pH 7.0. The Hill coefficient for N‐carbamoyl‐β‐alanine was 2.0, but the cooperativity decreased to 1.0 in the presence of 1 mM propionic acid. The K value towards N‐carbamoyl‐β‐alanine was calculated to be 0.17 mM from Hill plots and the K m value was determined to be 0.06 mM from replots of the apparent K m vs propionic acid.
Biochimica et Biophysica Acta | 1990
Nanaya Tamaki; Masae Kaneko; Mariko Kikugawa; Shigeko Fujimoto
Abstract The conversion of (R)- to (S)-β-aminoisobutyrate was observed in the presence of d -3-aminoisobutyrate-pyruvate aminotransferase, aminobutyrate aminotransferase, pyruvate and l -glutamate. The reverse reaction was also found in the presence of 2-oxoglutarate and l -alanine. Neither d -3-aminoisobutyrate-pyruvate aminotransferase nor aminobutyrate aminotransferase revealed a racemase activity of the enantiomorphs.