A simple and exact determination method of cocarboxylase is reported. A sample is subjected preliminarily to ion exchange resin chromatography and the cocarboxylase fraction is separated from thiamine esters and other impurities. The pH of the fraction is brought to less than 4 and the optical density is determined at 270mμ. The recovery is proved to be satisfactory.

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1. “Catechothiamine” and “Hydroquinothiamine”, thiamine degradation products by pyrocatechol and hydroquinone respectively, were isolated in a crystalline form. They were proved to be identical with “Rutinothiamine”. It was finally demostrated that they were all identical with thiamine disulfide of Zima by ultraviolet and infrared absorption spectra, paper chromatography, elementary analyses, and mixed melting-point determination.
2. The mechanism of thiamine degradation by thermostable factors is presented.

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L-Ascorbic acid-decomposing activity was tested with various yeasts and bacteria. In 8 known species of yeasts and 15 species of bacteria no such activity was found. But 9 species of bacteria having a strong ascorbic acid-decomposing activity were separated from natural sources, i.e. soil, water, plants and excrements of animals. These bacteria grown in the media containing 1 per cent L-ascorbic acid decomposed the vitamin to CO₂, water and a few organic acids. From the results of the studies on their microbiological properties, it was ascertained that 6 out of the 9 species belong to Micrococcus, probably the varieties of M. varians Migula, and the other 3 species to the variety of Nocardia farcinica.

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1. Both brain glutamic-oxaloacetic-, and aspartic-α-ketoglutaric transaminases as well as glutamic decarboxylase are inhibited when running fit is induced by OMP.
2. This inhibition is believed to be due to OMP-phosphate formed by the phosphorylation of OMP in the body.
3. When running fit is induced by hydroxylamine, both transaminases are not inhibited but brain glutamic decarboxylase is suppressed.
4. From these findings, inhibition of brain glutamic decarboxylase is considered to be an causal factor for the occurrence of the running fit.

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Growth hormone was demonstrated to inhibit B₆-enzyme systems of E. coli at relatively low concentrations.

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1. With cell-free extracts of Cl. acetobutylicum and E. coli, it was found that acetate was a 4-C-donor in the enzymatic conversion of 6, 7-dimethylribolumazine to riboflavin.
2. Presence of ribityl side chain was ascertained to be important in the enzymatic synthesis of riboflavin, and the formation of lumiflavin or lumichrome from 8-N-methyl-6, 7-dimethyllumazine or 6, 7-dimethyllumazine was not observed.
3. With Cl. acetobutylicum, E. coli and Er. ashbyii, respectively, 6, 7-dimethyllumazine was enzymatically synthesized from 4, 5-diaminouracil.
4. Riboflavin was synthesized both enzymatically and chemically from G₂ Compound isolated from the culture filtrate of Cl. acetobutylicum.

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1. The enzyme catalyzing the conversion of 8-N-ribityl-6, 7-dimethyllumazine to riboflavin was found in Er. ashbyii, beef liver, L. plantarum, Neurospora crassa, as well as in E. coli and Cl. acetobutylicum, in which its existence has already been reported.
2. The enzyme is widely distributed in nature, and among a number of organisms tested, the activity of Er. ashbyii was the highest.
3. The activity of the partially purified enzyme of E. coli neapolitanus was inhibited by sulfhydryl reagents such as p-chloromercuribenzoate and monoiodoacetate. A remarkable inhibition was also produced by several heavy metal ions at the concentration of 10^-2M, i.e., Ag, Hg, Cu, Zn and Fe. KCN, NaF and monofluoroacetate did not exert any inhibition at 0.01M.
4. The effect of the concentrations of 6, 7-dimethylribolumazine and of the enzyme as well as that of pH on the rate of riboflavin synthesis were examined.
5. For full activation of this enzyme, it requires the addition of such cofactors as ATP, DPNH and CoA. Acetyl phosphate is found to be replaceable for acetate and ATP, when the enzyme preparations of Cl. acetobutylicum and E. coli. were used.

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A simple colorimetric method for vitamin D has been described after removing steroids by methanol treatment and isolating the vitamin fraction by Superfiltrol chromatography. The conditions tested for the determination were given in detail. In the presence of much vitamin A, the correction for it is necessary. The limitation of this method for the presence of vitamin A is markedly less than that of alumina chromatography. The limit of A/D in I. U. of this method is ca. 20, but the vitamin can be roughly determined even at the ratio of 100.

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1. An arterial hypertension was developed in the rat fed a diet containing 3.5per cent sodium chloride for a period of 27 weeks and this hypertension was found to be accompanied by hypertrophy of the kidneys and adrenals, an increased excretion of urinary 17-ketosteroids, an elevated serum cholesterol level, a reduced activity of succinoxidase and a decrease in riboflavin level of the kidneys. On the contrary, no changes in succinoxidase activity and ascorbic acid level of the liver were observed.
2. An elevation of the blood pressure, a hypertrophy of the kidneys and adrenals, an increase in the urinary 17-ketosteroids and a decrease in the renal succinoxidase activity in the rats were somewhat prevented by a previous addition of ascorbic acid, riboflavin or choline to the diet.
3. The addition of riboflavin was effective to prevent an elevation of the blood pressure and the serum cholesterol level.
4. Significant histological changes were observed in the kidneys of the rats fed a salt-rich diet. The administrations of ascorbic acid, riboflavin or choline protected the histological changes induced by high-salt diet to a certain extent.

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