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Volume 73, Issue 2
Displaying 1-11 of 11 articles from this issue
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Retsu MIURAArticle type: Article
1999 Volume 73 Issue 2 Pages 73-82
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSFlavocoenzymes are extremely versatile in that they show broad potentiality in catalysis, as manifested in the wide range of the reactions catalyzed by flavoenzymes. In order for each of the flavoenzymes to express its specific function, the versatility of the coenzyme should be elegantly controlled. This control mechanism lies in the structure-reaction linkage. We have recently solved the high-resolution three dimensional structure of D-amino acid oxidase by X-ray crystallography. On the basis of the tertiary structure of the enzyme-substrate analog complex, the enzyme-substrate complex structure was modeled by means of molecular mechanics simulation. The simulated structure was not compatible with the hitherto recognized reaction mechanisms which require an amino acid residue acting as a catalytic base to abstract the subtrate α-proton. We have introduced two new mechanisms after analyzing the structure-reaction linkage based on the substrate-binding mode and the requirements that the reaction mechanism should suffice. One of them is called the "electronproton-electron transfer mechanism" and is characterized by two one-electron transfer processes intervened by a proton transfer, while the other distinguishes itself in ionic intermediates and is thus called the "ionic mechanism." In both of the mechanisms flavin N(5) rather than an amino acid residue acts as a base for abstracting the substrate α-proton and flavin C(4_a) is the site of electron acceptance from the substrate.View full abstractDownload PDF (995K) -
Kazuyo OKAYAMA, Masako FUKUSHIMA, Yukiko KUMAZAWA, Ryokuero SUZUEArticle type: Article
1999 Volume 73 Issue 2 Pages 83-87
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSAluminium(Al) accumulates on nervous tissue and bone, and causes unfavorable syndromes on nephropathy patients. It is well known that some organic acids accelerate aluminium absorption. So we, at first, induced nephropathy of guinea pig by giving HgCl_2, and examined the effects of ascorbic acid(AsA) on aluminium absorption and excretion. Guinea pigs were divided into 5 groups. They were low AsA+A1 group, low AsA group, high AsA+Al group, high AsA group, and control group. Except for the control group, kidneys were damaged by intaking of HgC1_2. After 7 weeks, they were sacrificed and Al contents in organs were measured by atomic absorption spectrophotometer. On bone, Al contents were extremely high in AsA administered groups. But in the control group, A1 content showed normal value.View full abstractDownload PDF (549K) -
Mami HIRAOKA, Keiko SHIBATA, Kazuto YASUDAArticle type: Article
1999 Volume 73 Issue 2 Pages 89-94
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSAs an initial step to decide reference intervals of serum total vitamin B_6 and blood total nicotinic acid level, blood vitamin B_6 and nicotinic acid concentrations were determined in a group of healthy female students, 21-22 years old, who were confirmed with vitamin B_6 and nicotinic acid intake above their Recommended Dietary Allowances(RDA_s) by dietary survey. Serum vitamin B_6 and blood nicotinic acid were determined by isocratic postcolumn HPLC and reverse phase HPLC, respectively. Vitamin intakes were assessed from dietary record for consecutive 3 days. The mean of daily vitamin B_6 intake was 1.35±0.53mg/day and 13.0% of subjects showed lower than 0.016 on the ratio of vitamin B_6 (mg) / protein (g) intake. A significant correlation was found between intakes of vitamin B_6 and protein. Reference interval of serum total vitamin B_6 level which was obtained from the subjects with their intake above their RDA was 4 〜17 (9.1±2.7) ng/ml. The mean intake of the daily nicotinic acid equivalent was 24.0±5.9mg/day which was the amount of nicotinic acid and nicotinic acid converted from tryptophan. There was no subject who showed nicotinic acid intake lower than RDA (6.6mg/1,000kcal energy). Reference interval of blood total nicotinic acid level was 285〜710 (478.2±97.5)μg/dl from the subjects with nicotinic acid intake above their RDA.View full abstractDownload PDF (618K) -
[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 95-98
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSDownload PDF (497K) -
[in Japanese], [in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 99-101
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
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[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 103-105
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
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[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 107-
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
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[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 109-114
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSDownload PDF (734K) -
[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 115-120
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSDownload PDF (636K) -
[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 121-122
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSDownload PDF (348K) -
[in Japanese]Article type: Article
1999 Volume 73 Issue 2 Pages 122-124
Published: February 25, 1999
Released on J-STAGE: December 26, 2017
JOURNAL FREE ACCESSDownload PDF (338K)
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