Thiamine pyrophosphate: An essential cofactor for the α-oxidation in mammals – implications for thiamine deficiencies?

The identification of 2-hydroxyphytanoyl-CoA lyase (2-HPCL), a thiamine pyrophosphate (TPP)-dependent peroxisomal enzyme involved in the α-oxidation of phytanic acid and of 2-hydroxy straight chain fatty acids, pointed towards a role of TPP in these processes. Until then, TPP had not been implicated in mammalian peroxisomal metabolism. The effect of thiamine deficiency on 2-HPCL and α-oxidation has not been studied, nor have possible adverse effects of deficient α-oxidation been considered in the pathogenesis of diseases associated with thiamine shortage, such as thiamine-responsive megaloblastic anemia (TRMA). Experiments with cultured cells and animal models showed that α-oxidation is controlled by the thiamine status of the cell/tissue/organism, and suggested that some pathological consequences of thiamine starvation could be related to impaired α-oxidation. Whereas accumulation of phytanic acid and/or 2-hydroxyfatty acids or their α-oxidation intermediates in TRMA patients given a normal supply of thiamine is unlikely, this may not be true when malnourished. Received 23 December 2005; received after revision 10 April 2006; accepted 28 April 2006     

Effect of tea consumption on the levels ofα-ketoglutarate and pyruvate dehydrogenase in rat brain

Summary Administration of tea to rats fed on a normal diet results in a marked drop in brain levels of total thiamine as well as of -ketoglutarate and pyruvate dehydrogenase activities. The patterns of decrease in both enzyme activities are similar to that of total thiamine content; they drop to about 65% of the control at 14–20 weeks after continuous consumption of tea.Supported by a grant from the International Foundation for Science (IFS), Sweden.     

Physiological studies on the effects of nutritional imbalance on the central nervous system. II. Effects of thiamine deficiency on oxidative enzymes in the brain of chicken, Gallus domesticus.

The activitiy levels of succinate dehydrogenase, glutamate dehydrogenase and pyruvate dehydrogenase in the fore, mid and hind brain regions of the thiamine deficient chicken, Gallus domesticus were determined. The activity levels of succinate dehydrogenase and glutamate dehydrogenase in all the 3 regions of brain showed augmentation on inducing thiamine deficiency. In contrast the activity levels of pyruvate dehydrogenase decreased in the brain of thiamine deficient animals. It is suggested that these changes in the oxidative enzymes indicate disturbance caused in the operation of the tricarboxylic acid cycle in thiamine deficiency.     

Physiological studies on the effects of nutritional imbalance on the central nervous system. II. Effects of thiamine deficiency on oxidative enzymes in the brain of chicken,Gallus domesticus

Summary The activity levels of succinate dehydrogenase, glutamate dehydrogenase and pyruvate dehydrogenase in the fore, mid and hind brain regions of the thiamine deficient chicken,Gallus domesticus were determined. The activity levels of scccinate dehydrogenase and glutamate dehydrogenase in all the 3 regions of brain showed augmentation on inducing thiamine deficiency. In contrast the activity levels of pyruvate dehydrogenase decreased in the brain of thiamine deficient animals. It is suggested that these changes in the oxidative enzymes indicate disturbance caused in the operation of the tricarboxylic acid cycle in thiamine deficiency.     

Active transport of dimethialium inSaccharomyces cerevisiae

Summary Dimethialium, a derivative of thiamine which has a methyl group in place of hydroxyethyl group at the 5-position of the thiazole moiety, was found to be accumulated in nonproliferating cells ofSaccharomyces cerevisiae by the same transport mechanism for thiamine. The results strongly support the supposition that thiamine as well as dimethialium can be transported and accumulated without obligatory phosphorylation in yeast cells, since dimethialium is not phosphorylated by yeast thiamine pyrophosphokinase.We wish to thank the late Dr S. Yurugi, Takeda Research Laboratories, for a generous gift of dimethialium.     

Occurrence of thiaminase II in Saccharomyces cerevisiae

It was found that cell-free extracts of Saccharomyces cerevisiae contain thiaminase II which hydrolyzes thiamine and thiamine analogs. The possible involvement of this enzyme and thiamine-synthesizing enzymes in thiamine production from thiamine antagonists is discussed.     

Effect of lipophilic cations on thiamine transport system in isolated rat hepatocytes

The effect of lipophilic cations such as triphenylmethylphosphonium, tetraphenylphosphonium and tetraphenylarsonium in addition to dibenzyldimethylammonium on thiamine transport in isolated rat hepatocytes was studied. Lipophilic cations at the concentration 10 microM almost completely inhibited thiamine uptake. Kinetic studies showed that these compounds were competitive inhibitors with a very high affinity. These results suggest that lipophilic cations in addition to quaternary ammonium compounds also share a common binding site for thiamine in isolated rat hepatocytes.     

Thiamine-binding activity of Saccharomyces cerevisiae plasma membrane

The specific binding activity to [14C]thiamine was found to be located in hte plasma membrane of Saccharomyces cerevisiae. The activity was inhibited by several thiamine analogs and it was hardly detectable in the plasma membrane from a thiamine transport mutant of Saccharomyces cerevisiae. Some properties of the thiamine-binding activity of yeast plasma membrane are discussed in connection with those of the thiamine transport system.     

Thiamine triphosphate metabolism and its turnover in the rat liver

Summary When rats were injected with a thiamine disulfide derivative, the content of thiamine triphosphate (TTP) in the liver doubled within 3 h after a preceeding rise in thiamine pyrophosphate; it then returned to the basal level within the next 3h, indicating a net increase of TTP in vivo and its rapid turnover.     

Inhibition of thiamine transport in baker's yeast by methylene blue

Summary Methylene blue was found to inhibit thiamine transport competitively (K_i=0.63 M) in baker's yeast. The dye was also effective in abolishing the growth inhibition ofSaccharomyces cerevisiae by pyrithiamine which is known to be taken up by a common transport system for thiamine in yeast cells. A possible mechanism for the inhibition by methylene blue of the thiamine transport system in baker's yeast is discussed.     

Thiamine-binding activity ofSaccharomyces cerevisiae plasma membrane

Summary The specific binding activity to [¹⁴C]thiamine was found to be located in the plasma membrane ofSaccharomyces cerevisiae. The activity was inhibited by several thiamine analogs and it was hardly detectable in the plasma membrane from a thiamine transport mutant ofSaccharomyces cerevisiae. Some properties of the thiamine-binding activity of yeast plasma membrane are discussed in connection with those of the thiamine transport system.     

Effects of hypochlorite on thiamine and its derivatives

Thiamine and its phosphorylated derivatives reacted with hypochlorite with reaction rates following the order: thiamine greater than thiamine monophosphate greater than thiamine diphosphate from pH 4.0 to 6.5. At least one unknown transient intermediate was formed and at least one non-thiochrome product was fluorescent. Chemiluminescence was also observed.     

Interaction of basic dyes with the thiamine transport system inSaccharomyces cerevisiae

Summary Basic dyes such as methylene blue and triphenyltetrazolium chloride were found to inhibit thiamine transport inSaccharomyces cerevisiae. Conversely, the reduction of methylene blue and triphenyltetrazolium chloride by yeast cells was inhibited by thiamine. A thiamine transport mutant ofSaccharomyces cerevisiae showed decreased utilization of these dyes. From the results, the possibility that the uptake of basic dyes may proceed via a membrane-bound thiamine-binding protein in the thiamine transport system of the yeast is discussed.This work was supported in part by a grant from the Ministry of Education, Science and Culture of Japan.     

Active transport of [32P]thiamine diphosphate inEscherichia coli

Summary Active uptake of [³²P]thiamine diphosphate byE. coli was analyzed using an improved method of gel filtration chromatography. The radioactive coenzyme was accumulated without dephosphorylation. From this result it was concluded that thiamine kinase is not involved in the membrane transport of thiamine inE. coli.We are indebted to Miss M. Abe for her technical assistance.     

Differential effects of opiates on the incorporation of [14C] thiamine in the central nervous system of the rat

Summary Opiate agonist (morphine), pure antagonist (naloxone), mixed agonist-antagonist (nalorphine) and analgesically inactive enantiomorph (dextrorphan) produced differential stereoselective effects on the incorporation of [¹⁴C] thiamine in the central nervous system of the rats. The possible role of thiamine in opiate effects and its implications are discussed.To whom reprint requests should be addressed. The authors thank Dr. S. J. Mulé, Assistant Commissioner and Director, ODAS Testing and Research Laboratory, for his kind interest and support and Mrs J. Vardy, Mr A. Kramer and Mr V. Aschettino for assistance.     

Pharmakologische Untersuchungen bei Thiaminmangel I. Änderungen des Katecholamingehalts im Gewebe

Summary (1) The increased tissue catecholamine level of the thiamine deficient rat was shown in the atrium, the ventricle, the brain cortex and in the spleen but not in the brain stem and the adrenal gland. (2) The increased response to tyramine of the thiamine deficient heart is most probably due to the high catecholamine level caused by thiamine deficiency. (3) The increased catecholamine content in the thiamine deficient rat does not result from the increased pyruvic acid.

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Herrn Professor Dr.F. Th. von Brücke zum 60. Geburtstag im Januar 1968 gewidmet.     

Occurrence of thiaminase II inSaccharomyces cerevisiae

Summary It was found that cell-free extracts ofSaccharomyces cerevisiae contain thiaminase II which hydrolyzes thiamine and thiamine analogs. The possible involvement of this enzyme and thiamine-synthesizing enzymes in thiamine production from thiamine antagonists is discussed.30 September 1986Acknowledgments. We thank the late Dr S. Yurugi, Takeda Pharmaceutical Industries, Osaka, for his generous gifts of dimethialium, 2-northiamine, -hydroxyethylthiamine, hydroxymethylpyrimidine, 2-norhydroxymethylpyrimidine and hydroxyethylthiazole. We also thank Prof. H. Nakayama, Yamaguchi Women's College, for his kind supply ofEscherichia coli 70–17 and 26–43.     

Influence of diet on plasma tryptophan and brain serotonin levels in mice

Groups of mice were maintained for up to 78 weeks on tryptophan restricted, protein restricted and control diets. Plasma tryptophan levels were significantly reduced by both forms of dietary restriction. Brain serotonin levels were significantly reduced only in mice on the tryptophan restricted diet, but not for mice on the protein restricted diet. The protein-restricted diet contains less of the large neutral amino acids which compete with tryptophan to enter the brain. It is known that protein restriction and tryptophan restriction extend lifespan. The results presented here suggest that extension of lifespan and lowering of brain serotonin are not related.     

Influence of diet on plasma tryptophan and brain serotonin levels in mice

Summary Groups of mice were maintained for up to 78 weeks on tryptophan restricted, protein restricted and control diets. Plasma tryptophan levels were significantly reduced by both forms of dietary restriction. Brain serotonin levels were significantly reduced only in mice on the tryptophan restricted diet, but not for mice on the protein restricted diet. The protein-restricted diet contains less of the large neutral amino acids which compete with tryptophan to enter the brain. It is known that protein restriction and tryptophan restriction extend lifespan. The results presented here suggest that extension of lifespan and lowering of brain serotonin are not related.     

Influence of sodium balance on atrial natriuretic factor in rats with one-kidney, one-clip renal hypertension

The influence of sodium intake on the gene expression and circulating levels of atrial natriuretic factor (ANF) was investigated in unanesthetized rats with one-kidney, one-clip renal hypertension. After clipping, the rats were maintained for 3 weeks either on a salt-deficient (n = 11) or a regular-sodium diet (n = 10). Animals which had received the regular-sodium diet exhibited significantly higher ANF mRNA levels in their right and left atria than salt-restricted animals, whereas there was no significant difference in plasma ANF levels.