1) A Lineweaver-Burk plot of tryptophan aminotransferase activity in the supernatant fraction from rat liver gave a hyperbolic curve. This suggested that the activity might be due to the simultaneous actions of two or more enzymes with different Km values.
2) On DEAE-cellulose column chromatography of the supernatant from normal rat liver, tryptophan aminotransferase activity separated into two peaks, while that from the liver of rats after tryptophan or cortisol injection separated into three peaks. The second peak eluted from the latter seems to be an inducible enzyme. No aspartate, alanine, tyrosine, kynurenine, histidine or phenylalanine aminotransferase activities were detected in this fraction. The first peak eluted from DEAE-cellulose column had aspartate aminotransferase activity and the third peak had tyrosine aminotransferase activity.
3) On DEAE-cellulose column chromatography, the tryptophan aminotransferase activity in the supernatant fractions from the kidneys and hearts of normal rats, tumor cells (AH-130) and the livers of tumor-bearing rats showed the same elution pattern as that from the liver of rats after tryptophan or cortisol injection. The Km values for tryptophan of these enzymes in the second peaks were all similar. These results suggest that the aminotransferase enzyme in the second peaks from all these sources may be the same kind of tryptophan specific enzyme.

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The clinical effects of vitamin E have been investigated in 7 cases (3 adolescents and 4 adults) of purpura due to vascular changes caused by infection, drugs or of unknown etiology. Marked clinical improvements were observed following the oral administration of vitamin E (400 to 600mg of α-tocopherol nicotinate per day) in all cases. Six out of 7 cases showed remarkable improvement of petechiae following the vitamin E therapy alone. Complete disappearance of petechiae was observed following the administration of vitamin E for 5 days in 2 cases, 14 days in 4 cases and 21 days in 1 case, along with the improvements of other clinical symptoms.

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Experimental systems using non-growing cell of Eremothecium ashbyii to elucidate the mechanism of flavinogenesis were established in this paper.
1. It was found that vacuum infiltration of purines for 2, 3 and 5 min and moderate shaking of non-growing cell brought about a good reproducibility of the stimulatory effects on flavinogenesis by purines and furthermore, a higher flavinogenesis.
2. The addition of an inhibitor of protein synthesis, chloramphenicol, to the basal medium at the concentration of 6mM after 1 day of cultivation resulted in a 45.1% inhibition of the growth measured after 2 days of cultivation and a 65.1% inhibition of riboflavin production measured after 4 days of cultivation. On the other hand, the addition of an inhibitor of purine de novo synthesis, sulfanilamide at 4mM resulted in a 24.3% inhibition of the growth after 2 days and a 44.1% inhibition of riboflavin formation after 4 days respectively.
3. The addition of these drugs and another inhibitor of protein synthesis, cycloheximide to the non-growing cell medium brought about little effects on flavinogenesis and only cycloheximide showed a 25% inhibition of riboflavin production at 7mM.
4. It was elucidated from above results that non-growing cell under such the special conditions shows little or no synthesis of protein and purine derivatives but there occurs flavinogenesis to a fair extent.
5. It was found that xanthine is the most flavinogenic purine among various purines during these experiments.

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Purine metabolism in relation to the riboflavin biosynthesis was examined using non-growing cell of Eremothecium ashbyii.
1. It was found that xanthine is the most effective purine for flavinogenesis among various purines tested in the stimulation experiments using non-growing cell.
2. The UV light absorption spectra of purines in non-growing cell medium were determined during the incubation. The conversions of adenine to hypoxanthine at the earlier stages and hypoxanthine to xanthine at the later stages were detected. Furthermore, the conversion of adenine to hypoxanthine was found to be located endogenously.
3. The membrane transportable effects of purines were examined by photometrically determining the residual purines in the medium during the incubation and thus noticeable results which commonly have a unique plateau regions were obtained. However, any marked differences between added purines were not observed.
4. Fluctuation of purine pools in cell was followed, using cation exchange resin, Dowex-50×4 in the presence of various purines. Thus, guanine was found to be accumulative but adenine was not detected in cell. Moreover, xanthine did not convert to any other purines and guanine also was not convertible except for its conversion to xanthine.
5. Dynamic changes of purines in the 24 hr incubation medium were followed by the use of cation exchanger. However, the accumulation of particular purine derivatives was not observed.
6. Only the third nucleotide fraction in the water eluting fraction of the column chromatography by cation exchanger characteristically fluctuated with the incubation. This fraction was found to consist of adenosine monophosphate and guanosine monophosphate. The changes of these nucleotides seem to be closely related to flavinogenesis.
7. Xanthine contents inside and outside the cells at 24 hr of incubation were determined by using Florisil column and Dowex-50 column. Thus, guanine appeared to be converted to xanthine at the later stages of the incubation. Other purines were also well in accordance with the results of Summary 2.

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Of the tested thioether type thiamines, S-acetoxymethyl-O-acetylthiamine (BD 57), S-benzoyloxymethylthiamine (BD 76) and S-(1-benzoyloxyethyl) thiamine (BD 78) showed full thiamine activity while S-acetoxythiomethylthiamine (BD 116) and S-(1-benzoyloxybutyl) thiamine (BD 77) showed 81 and 17% of activity of equivalent mole of thiamine hydrochloride, respectively. BD 57, 76 and 78 were enzymatically converted into thiamine by liver microsomal fraction with ease in the describing order but BD 77 was hardly converted. These compounds were not uptaken by red blood cells in in vitro experiment. Oral administration of BD 57 to dogs caused much higher thiamine levels in blood, especially in blood cells, as compared with administration of thiamine hydrochloride. About 40 to 50% of the injected BD 57, 76, 78 or 116 were excreted as thiamine into the 24 hr urine, while about 30% were excreted after oral administration.

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Riboflavin cyclic 2′, 5′-monophosphate (RCMP) formed by the GTP-dependent riboflavin phosphate synthetase of Rhizopus was shown to have some cytocidal action on tumor S180A. In all our experiments, this action was significantly stronger than that of FMN or riboflavin.

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Six groups of Wistar rats were used to demonstrate effects of magnesium deficiencies on thiamine metabolism. Group I was fed both a thiamine and magnesium deficient diet, Group II a thiamine deficient and magnesium sufficient diet, Group III a thiamine adequate and magnesium deficient diet, Group IV a thiamine adequate and magnesium sufficient diet (control), Group V an excess thiamine and magnesium deficient diet and Group VI an excess thiamine and magnesium sufficient diet. Animals were sacrificed after four weeks and magnesium, thiamine and transketolase activities were determined in various tissues.
Magnesium concentration in blood cells, plasma and bone decreased markedly in the thiamine supplemented-magnesium deficient groups (Group III and V) compared to that in the group deficient in both thiamine and magnesium (Group I). This finding suggests that the thiamine deficiency inhibited utilization of magnesium. Thiamine content of the sciatic nerve, liver and kidney of the magnesium deficient rats were lower than in the magnesium sufficient rats. This suggests that magnesium plays a considerable role in the maintenance of thiamine in tissues. No decrease of thiamine was detected in the central nervous system of magnesium deficient rats. Tissue transketolase activity decreased markedly in thiamine deficient and thiamine-magnesium deficient rats (Group I and II). Addition of thiamine pyrophosphate to tissue homogenates of thiamine deficient rats (Group II) resulted in recovery of transketolase activity, however this phenomenon did not occur when rats were also deficient in magnesium (Group I).

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In addition to our previous findings on GLC and mass spectroscopic determination of vitamins D, extensive studies on the effect of interfering substances have presented a new simple GLC determination method of vitamin D₂ in the presence of vitamins A and E. Thus, by employing TLC before applying a sample for GLC evaluation, vitamin E and its related compounds which interfere the GLC determination are eliminated completely and the greater part of vitamin A is also removed in the form of anhydrovitamin A simultaneously. Exhaustive conversion of vitamin A into its anhydro derivative and removal of unreacted vitamin A from vitamin D are not necessary. The proposed method is a simple, inexpensive, accurate, and time-saving quantification method of vitamin D₂. Main advantages and limitation of the method are discussed in detail.

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The mechanism of formation of thiamine from ³⁵S-chloroethylthiamine and the metabolic pathway as well as the main metabolites of the compound in chick were studied. Thiamine was found to be formed by tissue segments from the lower small intestine, while only a little by the liver slices. The formation was dependent of the incubation temperature and inhibited by sulfhydryl inhibitors such as p-chloromercuribenzoate, N-ethylmaleimide and monoiodoacetic acid or by heat-denaturation. On the other hand, sulfhydryl compounds such as glutathione and cysteine could not show any stimulating effect on thiamine formation. The feces and intestinal contents could not metabolize chloroethylthiamine to thiamine and Neomycin did not depress the thiamine formation by the intestine, indicating that intestinal flora does not play a role in the thiamine formation. These results suggest that thiamine may be produced by an enzymatic reaction sensitive to SH-inhibitor in the lower small intestine. However, the main metabolic pathway was shown to be a nonenzymatic formation of chloroethylthiamine to thiamine anhydride, followed by an enzymatic oxidation to its sulfoxide and sulfone presumably by P-450 dependent mixed function oxygenase of liver microsomes. Thiamine acetic acid was also identified as a minor metabolite of chloroethylthiamine.

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