1. 2-methyl-4-amino-5-aminomethylpyrimidine inhibits brain glutamic decarboxylase. It also has an inhibitory effect on bacterial tyrosine decarboxylase.
2. The restoration of the glutamic decarboxylase inhibition by PAL phosphate differs according to whether the 2-methyl-4-amino-5-aminomethylpyrimidine comes in contact with the enzyme before or simultaneously with the substrate. Restoration takes place in the case of the latter but not in the former.
3. An inhibitory effect is also observed against brain ABA-KGA transaminase but there is no difference whether the contact is before or simultaneous.
4. This inhibition is overcome by PAL phosphate.
5. 2-methyl-4-amino-5-aminomethylpyrimidine inhibits brain PAL kinase. An apparent enhancement of activity was observed, however, in the case of PAL kinase purified from brewer's yeast.

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1. Brain glutamic decarboxylase is inhibited in the OMP-induced running fit, but γ-aminobutyric-α-ketoglutaric transaminase is not inhibited.
2. Both enzymes show normal activities when the seizure is prevented by pyridoxine.
3. MAAMP inhibits γ-aminobutyric-α-ketoglutaric transaminase to a greater extent than glutamic decaboxylase.
4. In preventing the OMP running fit with MAAMP, it is more effective to give it before OMP.
5. The inhibition of glutamic decarboxylase by OMP is slighter when the running fit is prevented by MAAMP.
6. Both glutamic decarboxylase and γ-aminnobutyric-α-ketoglutaric transaminase are inhibited in the thiosemicarbazide-induced running fit, but when the seizure is prevented by pyridoxine, there is no inhibition.
7. From these results, it is assumed that brain aminobutyric acid is decreased when the running fit occurs but is not reduced when the running fit is prevented by pyridoxine.

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The mechanism of inhibition of Escherichia coli communior tryptophanase by thyroxine, parotin and growth hormone was considered in relation to apoenzyme, metal ion and sulfhydryl group. Each hormone was found to show its own different attitude of inhibition.

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1. The unknown spot appearing in paper chromatograms of the whole body homogenates of mice is ascertained to be riboflavinyl-glucoside, with reference to absorption spectrum, R_F values using various solvent systems and the detection of glucose in the solution of riboflavinyl-glucose.
2. It was found that the body of a mouse contains only FMN and FAD, but no riboflavin and that riboflavin does not degrade in the body.
3. In the course of 24 hours after loading with riboflavin plus ATP, it was found that the courses of FAD and of riboflavinyl-glucoside are roughly parallel, that the amount of FAD was greatest when the glucoside was loaded, that the amount of FAD was increased with the increase of the glucoside and that the loading of FAD in vivo resulted in the increase of FMN alone.
4. From the above findings, the phosphorylation process could be explained by the process: riboflavin→riboflavinyl-glucoside→FAD↔FMN↔riboflavin (in which ATP participated), since FMN alone was obtained in vivo by the decomposition of FAD.

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1. When maltose was loaded together with riboflavin, flavinyl-glucoside was produced, accompanied with the rise of FAD production. From this, it is suggested that the flavinyl-glucoside of animal tissues is produced from riboflavin and maltose.
2. Contrasting actions of pyridoxal and vitamin K toward the phosphorylation of riboflavin were ascertained, i.e., the former activates the system; riboflavin→flavinyl-glucoside→FAD, and the latter activates the system, riboflavin→FMN↔FAD.

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The amounts of total and esterified riboflavin in the total 24-hour urine and in the blood of tuberculous patients, mild, moderate and severe, were determined and there was no significant difference among the severity of the disease, no riboflavin deficiency symptoms being apparent. However, it seems to reveal the differences of metabolism according to the condition of illness that the levels of riboflavin, especially of esterified forms, become higher, as the symptom advances for the better.
In the loading test, more than 2mg of riboflavin is required for every day loading. The loading was found to be more appropriate to carry out every day with small portion than once with a large amount, since the levels of riboflavin in blood before breakfast in the morning following the loading more elevated after receiving successive injections day by day than receiving an injection of the vitamin once. In case of successive loading with 2mg of riboflavin every day, more amount the vitamin was excreted in the urine by the severe than the mild, whereas in case of loading with the vitamin once, the less riboflavin was excreted in the urine, the milder was the symptom. It is possibly to be considered, that the mild patients have retained more riboflavin in the bodies than the severe prior to loading in case of loading once, and that the loaded riboflavin is utilized more by the mild patients than by the severe after successive loading with 2mg of riboflavin. The loaded riboflavin is thought to be phosphorylated, and activated by coupling with a protein; accordingly, FMN and FAD are considered to be better suited for the loading than riboflavin. It was in fact in agreement with the results of this experiment. In the case of every day loading, the levels of the vitamin in blood are elevated, so that it may not be necessary to consider especially the time of the loading.
That more esterified riboflavin is excreted in urine after loading with the vitamin together with ATP than otherwise is thought to be due to the metabolic condition of phosphorylated compounds. After administering ATP together with riboflavin, the level of the vitamin in erythrocytes was higher than without ATP, suggesting that ATP is participated in the penetration of the vitamin in the cells.

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Several antibiotics inhibited D-amino acid oxidase of hog kidney. Among them, penicilline, p-amino salicylic acid, sulfanilamide and oxytetracycline inhibited the enzymic activity by competition with either FAD or D-alanine. Chlortetracycline, tetracycline and erythromycin inhibited the enzymic activity by competition with FAD but not with D-alanine. Chloramphenicol and isonicotinic acid hydrazide inhibited the enzymic activity by competition with D-alanine rather than with FAD. Streptomycin had little effect on the enzymic activity.
The mechanism of the symptoms resembling those of ariboflavinosis following administrations of antibiotics was discussed to some extent. A possibility that binding of certain antibiotics to a flavoenzyme by competition with FAD might result in ariboflavinosis was suggested.

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Using Aerobacter aerogenes and Eremothecium ashbyii, chemically synthesized 4-N-ribitylamino-5-aminouracil was converted enzymically into riboflavin via 6, 7-dimethylribolumazine in the presence of acetoin. It is proposed that acetoin is enzymically oxidized to diacetyl and then it is cyclized spontaneously with diaminouracil compound forming lumazine compound. This reaction step does not require any energy-rich compound such as ATP in contrast to riboflavin synthesis from 6, 7-dimethylribolumazine. It was shown in Er. ashbyii that acetoin is formed from two molecules of acetaldehyde in the presence of cocarboxylase.

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1. An extract of E. coli catalyzed the successive transglycosidation between sucrose and B₂, synthesizing various B₂-compounds of oligosaccharides, containing either glucose or fructose.
2. Tentative structures of these B₂-compounds were characterized by paper chromatographic isolations, followed by partial acid hydrolysis.
3. B₂-fructoside synthesized by E. coli, was isolated in a crystalline form and its chemical properties were found to be identical with those of B₂-fructoside synthesized by Asp. oryzae.
4. It was found that glucose, α-methylglucoside and α-glucose-1-phosphate inhibited the transglucosidation, while fructose preferably inhibited the transfructosidation.
5. Raffinose was capable of replacing sucrose as a fructosyl donor, but fructose was hardly utilized.

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1. A biosynthetic reaction to form FAD from FMN and ATP was investigated, using a partially purified enzyme preparation obtained from E. coli.
2. The pH range for optimal activity is found to be 7.8 to 8.2 and the optimal temperature is 37° for the synthesis of FAD.
3. Mg²⁺ activates the enzyme and its optimal concentration is around 3×10^-3M.
4. The enzyme specifically requires FMN and ATP in the formation of FAD and requires PP for the breakdown of FAD.

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