1. FAD was adsorbed on several commercial active carbon powder, with the capacity of from 10 to 15% of their weight. It was eluted with basic solvents more easily than with acidic solvents. Of the solvents tested, the most adequate were pyridine-water (1:1) and lutidine-water (2:3). The FAD adsorbed on active carbon was recovered in a yield of 80% or more after five successive elutions with lutidine-water (2:3) using 10 fold volume of the carbon weight. No purifying effect was observed in the above process.
2. FAD with neary 90% purity was obtained from the crude FAD preparation through formation of barium and silver salts and removing the metal ions. This purifying effect was principally due to the silver salt process and the yield was about 70% including the succeeding process.

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1. The transfuctosidase which catalyzed the fructosyl transfer from sucrose to B₂, has been isolated from the cell extract of E. coli. The enzyme showed a maximum activity at pH 7.4 and at 37° in glycine buffer.
2. The properties of the enzyme, particularly with regard to its donor and acceptor requirements, were investigated.

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1. Enzymatic transglycosidation relating to B₂ was accelerated by irradiation of ultraviolet light.
2. Photochemical glycosidation of B₂ was demonstrated by irradiating the reaction solution containing B₂ and saccharide with ultraviolet light. The reaction optimally proceeded at about pH 4.2, and the action spectrum of the photoglycosidation was found to coincide with the absorption spectrum of B₂. Lumiflavin inhibited the glycosidation in competition with B₂.
3. The mechanism of the photoglycosidation was postulated in relation to that of the enzymatic transglycosidation.

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Thiamine and TDP inhibited D-amino acid oxidase of hog kidney. The inhibitory action of thiamine was stronger than that of TDP. The type of the inhibition was an intermediate form between competitive inhibition with either FAD or D-alanine and non-competitive one. As the mechanism of the increased excretion of riboflavin in urine following administration of large amounts of thiamine, a possibility that binding of thiamine or TDP to flavinenzyme might result in the release of FAD was suggested.

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1. Coprophagy by rabbits was studied by fitting them with collars which prevented coprophagy, and a special mucous feces covered with mucoprotein-substance was found to be excreted.
2. Complete separation of pink-colored mucous film was made from the mucous feces, and the film was proved to be chiefly composed of mucoprotein and vitamin B₁₂.
3. From the above findings, the pink-colored mucous film obtainable from fresh mucous feces seems to be nothing but a kind of vitamin B₁₂-mucoprotein-complex formed by the flora in the digestive tract, and the chemical nature is supposed to be quite similar to a kind of intrinsic factor.

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1. The apoenzyme activity of α-ketoglutarate oxidase system in the tissue of B₁₂-deficient rat studied in vitro under various addition of B₁₂, cytochrome, niacinamide, DPN, DPT, lipoic acid, CoA, ATP, FAD and glutathione. The decrease of the apoenzyme activity in B₁₂-deficient rats was always recognized in the uptake of O₂ by α-ketoglutarate oxidation system.
TABLE III Uptake of O₂ by α-Ketoglutarate Oxidation System in Washed Liver Homogenate of B₁₂-deficient Rats and of Rats Receiving B₁₂
2. The animals receiving 0.2μg of B₁₂ per os daily before experiments showed always an increased apoenzyme activity of α-ketoglutarate oxidase system.
3. The results seem to lead to the conclusion that vitamin B₁₂ contributes to the activation of the apoenzyme in α-ketoglutarate oxidase system in rats.

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1. The apoenzyme activities of pyruvate oxidase system in the liver of B₁-deficient rats were studied in vitro under various addition of DPT, CoA, lipoic acid, DPN, FAD, niacinamide, cytochrome c, ATP, glutathione, fumaric acid as well as pyridoxal-5-phosphate. A marked decrease of the apoenzyme activities in B₁-deficient rats were always demonstrated in the uptake of O₂ after adding pyruvate.
2. The apoenzyme activities of pyruvate oxidase system were recognized to be high in B₁-positive control rats fed a diminished caloric ration comparable to B₁-deficient groups.
3. The results seem to lead to the conclusion that thiamine contributes to the formation and activation of the apoenzyme in pyruvate oxidase system of rats as stated in the biochemical study on vitamin B₁₂.

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It was found that although little activation of papain was seen after a single addition of vitamin B₁₂ or glutathione, a marked increase was always recognized when the two factors were added together.

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By observing the effect of adding cellulose on body weight gain and on the amount of B₂ (total and FAD) in the blood and liver of B₂-deficient rats, it was ascertained that the B₂ synthesized in the intestine was available in the body.

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Range and average values were determined for the total and free form levels of the serum vitamin B₁₂ of the mouse, rat, guinea pig, rabbit, dog, horse, cow and calf. Liver vitamin B₁₂ levels of these animal species were also determined except the horse, cow and calf. The total B₁₂ levels of the serum had a wide variation among the various animal species. The species with the highest total B₁₂ level of the serum was the rabbit and the level was about one hundred times higher than that of human serum, which was lowest among the sera of the various species examined. The ratio of the free form to the total B₁₂ varied also widely among the species. The serum B₁₂ of the various species was classified by the mean ratios of the free form to the total into three groups. The liver vitamin B₁₂ levels of various species did not show such a remarkable diversity in contrast to the serum B₁₂ levels.

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1. The transglycosidase requiring B₂ as the specific acceptor of glycosyl groups was found in various kinds of microorganisms.
2. The optimal conditions and the activities of the transglycosidases were found to vary with the different strains of the microorganisms.
3. A close relationship was assumed to exist between the activity of the transglycosidases and the metabolic ability of the donor saccharides in microorganisms.

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In microbiological assay using Lactobacillus casei, dimethylribolumazine showed 1/1500 of riboflavin activity, whereas 6-methyl-7-hydroxyribolumazine showed neither growth-promoting nor antagonistic activities.
In curative experiments using riboflavin-deficient rats, neither dimethylribolumazine nor 6-methyl-7-hydroxyribolumazine was active as far as less than 2.5μmoles of each per rat per day was administered orally or intraperitoneally.

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1. In the absorption spectrum of the purified clearing factor two absorption maxima were recognized, i.e., 270-280 and 410-420mμ.
2. Lipolytic activity reduced by dialysis was recovered by pyridoxal phosphate, but not by heparin. It is probable that one component necessary for the activity of the lipolytic system is pyridoxal phosphate.
3. Optimal pH of the enzyme activity was 8.0.
4. The enzyme was shown to exist in albumin fraction electrophoretically.
5. The enzyme was inhibited by protamine sulfate, quinine sulfate, pCMB and heparin, but not by glutathione.

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1. 149 male albino rats were maintained for 4 weeks on a basal diet.
2. The rats were divided into 5 groups, each group receiving respectively as daily dietary supplement, 0, 0.5, 50, 100, 150mg α-tocopheryl acetate per day.
3. Plasma tocopherol levels were determined on all animals after stunning.
4. Plasma tocopherol levels are related to the log-dose of α-tocopheryl acetate administered daily, by the equation: y²-29.1xy+6.77x²+150.98y-36.1x=0

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Vitamin A and β-carotene form with SbCl₅ color substances having an absorption maximum at 620mμ, at which wavelength the colorimetric estimation can be easily and rapidly carried out.
Sufficient color for estimation is obtained by adding 0.01ml of SbCl₅-chloroform solution containing 468mg of SbCl₅ per ml to 3.5ml of sample chloroform solution.
Staining the glass by the SbOCl formed in the procedure was insignificant with the use of SbCl₅.

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