An adduct of phenylglyoxal with thiamine was readily converted to phenylglyoxylate and thiamine by the action of organic hydride acceptors such as 2, 6-dichlorophenol indophenol, trityl cation, 2-methyl-3-benzylidene-indolenium salt and N-methylnicotinamide. Similar hydride transfer reaction was observed for the adduct of methylglyoxal with thiamine. Direct conversion of phenylglyoxal to phenylglyoxylate by 2, 6-dichlorophenol indophenol was found to occur in the presence of TPP and base. The results indicate a new catalytic role for thiamine in the conversion of α-ketoaldehyde to α-ketoacid.

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The influence of vitamin E on the adenosine diphosphate (ADP) induced platelet aggregation was studied, and the following results were obtained. In these experiments, the solutions of α-tocopheryl acetate (2.5mg/ml) and α-tocopheryl acetophosphate (2.5mg/ml) were used.
1) When 0.5mg of α-tocopheryl acetate was added per 1ml of platelet rich plasma (PRP) 2 hours prior to experiment, it inhibited ADP (which was added 1μg per 1ml of PRP) induced platelet aggregation.
2) Addition of 0.15 or 0.3mg of α-tocopheryl acetophosphate per 1ml of PRP just prior to experiment evidently inhibited ADP induced platelet aggregation.
3) Addition of 0.1 or 0.2mg of α-tocopheryl acetate per 1ml of PRP rather promoted the platelet aggregation induced by ADP. The same effect was also observed when the solvents of α-tocopheryl acetate solution (equivalent volumes to 0.1, 0.2 and 0.5mg α-tocopheryl acetate) were added.

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Mitochondrial membrane of the liver from vitamin D deficient rats was found to be more fragile, when exposed to calcium ion, than that from normal rats. Malate dehydrogenase (MDH: EC 1.1.1.37), released from isolated mitochondria, was used as a parameter to assess the disruption of mitochondrial membrane.
Oral supplementation with vitamin D₃ restored the fragility of mitochondrial membrane toward normal, suggesting that vitamin D₃ or its active metabolites play a role in maintaining the integrity of mitochondrial membrane.

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Properties of the complementary components, component A and component B, necessary for the conversion of D-tetrose to the corresponding polyol and acid were studied.
The results of the present experiments indicate that component A consists of two separable factors, NAD and an enzyme which catalyzes the reduction of D-erythrose in the presence of NADH, and that component B has an enzyme activity which catalyzes the oxidation of D-erythrose in the presence of NAD.
On the basis of these results, it can be postulated that two enzymes, namely an enzyme catalyzing the reduction of D-erythrose and an enzyme catalyzing the oxidation of D-erythrose, are involved in D-tetrose metabolism, and that the combined action of these enzymes contributes to the ability of the beef liver preparation to catalyze the transformation of D-tetrose.

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Riboflavin afforded the mutagenic effect on transforming deoxyribonucleic acid (DNA) from Bacillus subtilis through photodynamic action, and upon the addition of adenine to the irradiation mixture the mutagenic effect was greatly accelerated. Most of auxotrophic mutants among the transformants required tryptophan or tyrosine. The mutation was closely correlated with the photodynamic inactivation of the DNA, and it was suggested that both the inactivation and the mutation were caused by the selective photodegradation of guanine residues in DNA.

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The effects of riboflavin deficiency on muscle protein, RNA and DNA, and on the incorporation of ¹⁴C-amino acid into muscle proteins have been studied on rats receiving 16% protein diet, or 16% protein diet followed by protein-free diet or 16% protein diet followed by protein-free diet and 40% protein diet. In each of the dietary conditions, protein content, RNA/DNA and protein/DNA ratios in muscle were found to be decreased in riboflavin deficiency. The incorporation of ¹⁴C-amino acid into muscle proteins decreased in riboflavin-deficient rats receiving either 16% protein or 16% protein diet followed by protein-free diet and 40% protein diet. But in riboflavin-deficient rats receiving protein-free diet following 16% protein diet, the incorporation of ¹⁴C-amino acid into muscle proteins was found to be enhanced. It has been suggested from these studies that decreased protein content in muscle of riboflavin-deficient rats in each of the dietary conditions is due to both reduced synthesis and increased catabolism of proteins, and the catabolism of muscle proteins in riboflavin-deficient rats is intensive when they receive protein-free diet.

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Rats were made deficient by thiamine deprivation and the enzyme activities of α-keto acid dehydrogenases and transketolase were measured with or without addition in vitro of thiamine diphosphate in liver mitochondria and in supernatants of liver homogenate, respectively.
The activities of pyruvate and 2-oxoglutarate dehydrogenases were determined by a spectrophotometric method according to Massey, that of transketolase determined by Racker's method. The values of enzyme activity as well as the thiamine contents in the preparations were compared with those of the animals whose deficiencies were restored by thiamine administration. The thiamine deprivation resulted in a significant decrease of these enzyme activities accompanied with the decrease of thiamine contents. However, the α-keto acid dehydrogenase in liver mitochondria of deficient rats were almost restored to normal levels by an in vitro addition of thiamine diphosphate to the enzyme reaction mixture, while the restoration of transketolase in the supernatant of liver homogenate was not observed by the addition in vitro of thiamine diphosphate. This would suggest a decrease of apoenzyme of transketolase caused by thiamine deficiency in contrast to those of α-keto acid dehydrogenase.
These findings reflect to the results that only once administration of thiamine, in vivo, caused a prompt restoration of α-keto acid dehydrogenase, while the restoration of transketolase was not sufficient with once administration of thiamine in spite of the rapid recovery of thiamine contents. The restoration of transketolase needed a prolonged administration of thiamine to return to normal levels. On the other hand, thiamine deficiency had no effect on the thiamine diphosphate-independent enzyme, thiamine pyrophosphokinase, as shown in the fact that the decreased thiamine contents in enzyme extracts returned promptly to normal by thiamine administration. And also a large dose administration of thiamine to normal rats caused no induction of the thiamine diphosphate-dependent enzymes.

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It was found that Schizophyllum commune which produced L-malate through CO₂-fixation process with a phosphoenolpyruvate carboxytransphosphorylase-like enzyme required thiamine. Upon the addition of oxythiamine at a concentration of 100μg/100ml, both the L-malate production and the glucose consumption were inhibited about 50%, while the conversion of glucose to L-malate was inhibited only 10%. The optimum concentration of thiamine to be added in the medium for the L-malate fermentation was 0.5μg/100ml. Upon the addition of 100μg/100ml thiamine, both the yield of L-malate and the conversion degree of glucose to L-malate were reduced about 50%, while the glucose consumption was not affected. One of the effects of thiamine appears to be a stimulative action on pyruvate decarboxylation. The optimum amount of thiamine to be added for the growth of the mold seemed to be more than 10μg/100ml.

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To investigate the influence of pantothenic acid deficiency on mitochondria, Saccharomyces cerevisiae, a pantothenate requiring strain isolate from a commercial baker's yeast was cultured with a pantothenate sufficient (200μg/liter) and a deficient (10μg/liter) medium. These microorganisms were observed morphologically with the electron microscope and analyzed for the lipid composition. And it was recognized that in pantothenate sufficient cells the existence of mitochondria was clear enough, but in the deficient cells the membrane structure of mitochondria was not proved. However, when pantothenate was sufficiently added to the cells in the deficient medium at the exponential phase the formation of mitochondria was detected after 18 hours as in the sufficient cells.
In the pantothenate deficient cells, the formation of lipids was markedly inhibited, and phospholipid constituted was almost 85% of the total lipid. And the amount of ³²P incorporated into the deficient cells was two times that in the sufficient cells, but the ratio of the count of phospholipid-³²P relative to the total was somewhat lower than that of the sufficient cells.
In the pantothenate sufficient yeast, the principal fatty acid in total lipid, neutral fat and phospholipid was found to be palmitoleic acid followed by oleic acid regardless of the kind of lipid. In contract, in the deficient cells, oleic acid was the principal component and palmitoleic acid followed it. These results may suggest that (I) pantothenate deficiency affects the membrane formation through the disturbance of lipid metabolism and (II) the organism plays an economical control on the fatty acid synthesis in the deficient condition.

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The cell wall and ribosomes of Lactobacillus leichmannii ATCC 7830, a vitamin B₁₂-requiring organism, have been shown to inhibit the cobamide coenzyme-dependent propanediol hydro-lyase (EC 4.2.1.28) reaction. A B₁₂-binder (polypeptide) of the wall was isolated and purified as a B₁₂-polypeptide complex (4). The complex, when treated with an alkaline solution, resulted in detachment of B₁₂ from the polypeptide. The free polypeptide, upon neutralization, could bind B₁₂ again and cobamide coenzyme as well, thus capable of inhibiting the enzyme reaction. Comparison was also made of this polypeptide with a hog intrinsic factor preparation in the inhibition.

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