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Noboru SUZUKI
Article type: Article
1974 Volume 48 Issue 12 Pages
521-537
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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The enzymatic systems for the biosynthesis and metabolism of folate coenzymes in plants were investigated. The enzymes detected were dihydrofolate reductase, formyltetrahydrofolate synthetase, methenyltetrahydrofolate cyclohydrolase, methylenetetrahydrofolate dehydrogenase, and 5'-phosphoribosyl-5-amino-4-imidazolecarboxamide (AICA-ribotide) formyltransferase. They were widely distributed in higher plants and were partially purified from pea seedlings respectively, and their properties were investigated. Folate antagonists retarded the growth of germinating pea seeds, and also inhibited potently the dihydrofolate reductase purified from pea seedlings. These facts suggest that the formation of folate coenzymes in pea seedlings might be blocked in the reduction of dihydrofolate to tetrahydrofolate. In such"folate-deficient"pea seedlings, AICA-ribotide, known as an intermediate in the biosynthesis of purine nucleotide, was found to be specifically accumulated. This compound was isolated from large amounts of "folate-deficient"pea seedlings and characterized as AICA-ribotide. It was the first case to isolate this compound from higher plants. The results suggest that the biosynthetic pathway of purine nucleotides in plants is similar to that of microorganisms and animal tissues. Furthermore, it was evidenced enzymatically that the AICA-ribotide is metabolized by catalytic action of AICA-ribotide formyltransferase in the presence of 10-formyltetrahydrofolate as coenzyme. 10-Formyltetrahydrofolate is presumably synthesized by two enzyme systems in plants. One is by catalytic action of formyltetrahydrofolate synthetase, and the other by methenyltetrahydrofolate cyclohydrolase and methylenetetrahydrofolate dehydrogenase. Intracellular distribution of these folate-linked enzymes in pea seedlings were investigated. Major portions of their activities were found in the cytoplasmic soluble fraction. A possible pathway for the synthesis and metabolism of folate coenzymes in plants is discussed.
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Isamu UTSUMI, Kiyoshi HARADA, Hiroshi MIURA
Article type: Article
1974 Volume 48 Issue 12 Pages
539-543
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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The effect of cobalamins on the oxidation of thiol form of thiamine was investigated. When 59.4 μmoles of thiamine was incubated with 0.1 μmole of aquocobalamin (OH-B_<12>) in borate buffer (pH 9.4) under aerobic conditions at 37℃ for 2 hours, about 36 μmoles of thiamine was oxidized to thiamine disulfide. The amount of oxygen utilized to oxidize 4 moles of thiamine was found to be 1 mole. The spectrophotometric investigation indicated that reduced cobalamin, B_<12r>, is formed as a catalytic intermediate in the oxidation of thiamine. From these results, it was concluded that the oxidation of thiamine is catalyzed by traces of OH-B_<12>. The catalytic activity of cobalamin analogs decreased in the order of hydroxocobinamide>cyanocobinamide>OH-B_<12>>DBCC, cyanocobalamin The mechanism of the catalytic reaction was discussed.
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Mitsuko ABE, Takahiro NISHIMUNE, Ryoji HAYASHI
Article type: Article
1974 Volume 48 Issue 12 Pages
545-549
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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Pyridoxine, pyridoxamine and pyridoxal were separated quantitatively from each other by gel filtration chromatography on Sephadex LH-20 (1.35×195 cm) using 5% propanol in 10 mM potassium phosphate buffer (pH 6.6). Their phosphates were also separated quantitatively by Sephadex G-15 column (1.35×195 cm) and 0.1M potassium phosphate buffer (pH 6.6). Each column and fraction collector was shielded from light by covering them with black paper. The procedures were proposed as methods for the quantitative determination of various types of vitamin B_6 compounds.
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Nobuyasu MIZUNO, Hiroko TAKAGI, Kayoko MUKAI, Miyako HATO, Akira KAMAD ...
Article type: Article
1974 Volume 48 Issue 12 Pages
551-556
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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Pyridoxine 3,4-dioctanoate (PIN-3,4DO) was readily changed into pyridoxine 4,5-dioctanoate (PIN-4,5DO) under alkaline treatment with 0.1 N KOH at room temperature. This rearrangement also occured with pyridoxine 3,4-dilaurate and pyridoxine 3,4-dipalmitate at the same condition. Solubility in organic solvents and molar extinction of PIN-4,5DO and PIN-3,4DO were studied.
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Tetsuo TORAYA, Kazumoto OHASHI, Hiroshi UENO, Saburo FUKUI
Article type: Article
1974 Volume 48 Issue 12 Pages
557-563
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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Vitamin B_<12> was succinylated by reaction with succinic anhydride to yield O^<2'>-succinyl-, O^<5'>-succinyl-, and O^<2'>, O^<5'>-disuccinyl-cyanocobalamin. Biochemical studies on the three succinyl derivatives of vitamin B_<12> demonstrated that the α-ribose moiety of the nucleotide ligand is physiologically much important-especially for the binding of vitamin B_<12> to the apoprotein of coenzyme B_<12>-dependent diol dehydrase and for the uptake of this vitamin by Escherichia coli cells.
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Yukinobu UCHIYAMA, Kunio OKUDA
Article type: Article
1974 Volume 48 Issue 12 Pages
565-573
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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A vitamin B_<12> absorption test by simultaneous administration of human gastric juice (intrinsic factor)-bound ^<57>Co-B_<12> and free ^<58>Co-B_<12> was carried out in 10 control subjects, 5 patients with pernicious anemia, 1 with total gastrectomy and 4 with malabsorption syndrome. The test is equivalent to two Schilling tests with and without added intrinsic factor, but it is done in one test with the use of two isotopes. Radioactivities of two labels were measured in plasma and urine with time, and in 24 hour urine. Maximum radioactivities were found 8〜10 hours after oral administration. The 24 hour urinary excretion in the control was 17.4±7.3% for ^<58>Co-B_<12> and 17.9±6.0% for ^<57>Co-B_<12>, with a^<57>Co/^<58>Co ratio of close to unity. In malabsorption syndome, urinary excretion of both were extremely low but the ratio was almost unity. In pernicious anemia and in subjects with total gastrectomy, urinary excretion of ^<58>Co-B_<12> was 2.1±1.1%, and ^<57>Co/^<58>Co was 6.2±5.1. Thus, this dual isotope method is of diagnostic value similar to Schilling test done on two occasions. However, it was also found that some of the gastric juice bound B_<12> is exchanged in the digestive tract with free B_<12> and, that to minimize such errors, it is recommended that two doses be given with a two hours interval. In patients in whom complete urinary collection is difficult, or the flushing dose is unwanted, measurement of 8 hour plasma radioactivity may serve the same purpose.
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
575-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
575-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
575-576
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
576-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
576-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
576-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
576-577
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
577-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
1974 Volume 48 Issue 12 Pages
577-
Published: December 25, 1974
Released on J-STAGE: March 14, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
579-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
579-580
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
580-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
581-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
582-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
583-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
583-584
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
584-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
584-585
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
585-586
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
586-587
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
587-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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[in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
588-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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[in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
588-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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[in Japanese], [in Japanese], [in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
588-589
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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[in Japanese]
Article type: Article
1974 Volume 48 Issue 12 Pages
589-
Published: December 25, 1974
Released on J-STAGE: March 02, 2018
JOURNAL
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