B—Thiamine

B, Thiamin Coenzyme in pyruvate and a-ketoglutarate, dehydrogenases, and transketolase poorly defined function in nerve conduction Peripheral nerve damage (beriberi) or central nervous system lesions (Wernicke-Korsakoff syndrome)... 

Determination of structural features. The ultraviolet spectrum has been of value in the determination of the structure of several vitamins. Thus the presence of an a-naphthoquinone system in vitamin K was first detected by this means. Also the 4-methylthiazole and the 2 5-dimethyl-6-aminop U idine system was first identified in vitamin B (thiamine). a- and /3-Ionones can be distinguished since the former contains two conjugated chromophores and the latta three conjugated chromophores. 

The SP procedure of water-soluble vitamins from multivitamin tablets is particularly challenging due to the diverse analytes of varied hydrophobicities and pfC. Water-soluble vitamins (WSVs) include ascorbic acid (vitamin C), niacin, niacinamide, pyridoxine (vitamin B ), thiamine (vitamin Bj), folic acid, riboflavin (vitamin B2) and others. While most WSVs are highly water soluble, riboflavin is quite hydrophobic and insoluble in water. Folic acid is acidic while pyridoxine and thiamine are basic. In addition, ascorbic acid is light sensitive and easily oxidized. The extraction strategy employed was a two-step approach using mixed solvents of different polarity and acidity as follows ... 

Vitamin B thiamine the precursor to the coenzyme thiamine pyrophosphate. 

K-Lor, Slow-K, Micro-K, Klorvess, others) (Table VI-5) Pyridoxine [Vitamin B ] Thiamine [Vitamin BJ... 

Health and Safety Factors. Malononiirilc is usually available as a solidified melt in plastic-lined drums. Remclting has to he done carefully because spontaneous decomposition can occur at elevated temperatures, particularly above lOO C. in the presence of impurities such as alkalies, ammonium, and zinc sails. Occupational exposure to malononitrile mainly occurs by inhalation of vapors and absorption through the skin. Malononitrile has a recommended workplace exposure limn of 8 mg/m Uses. Malononitrile is extensively used in the life sciences industry The most important products ate vitamin B (thiamine) and bensulfuron-melhyl. a sulfonyl urea herbicide. Most other product uses fall under the. V-containing heterocycles. 

T Kawasaki. Vitamin B, thiamine. In AP De Leenheer, WE Lambert, HJ Nelis, eds. Modem Chromatographic Analysis of Vitamins. 2nd ed. New York Marcel Dekker, 1992, pp 319-354. 

Jansen and Donath isolated vitamin B, (thiamine) from rice polishings. 

Vitamin B, [thiamin) Men 1.2 mg/d Women 1.1 mg/d Coenzyme in the metabolism of carbohydrates and certain amino acids prevents beriberi No adverse effects have been reported ... 

B. Thiamine Destruction. Farrer (6) showed that one of the essential metabolites for fungal growth, thiamine, was destroyed in 2 hours at 100°C at pH 7. At the same temperature but at pH 8, destruction was complete in 1 hour and at pH 9 in 15 minutes. 

B, Thiamin Coenzyme in pyruvate and Peripheral nerve damage... 

Some of the vitamins in the coeiizymc form associate tightly wdth specific enzymes, but not via a covalent linkage. Immediately after biosynthesis on the ribosome, enzymes do itot contain their cofactor, and these are called apoenzymes. An eitzyme containing its required cofactor is called a hoLoenzyme, With removal of the cofactor, the enzyme is also called an apoenzyme. The enzymes that exist in apoenzyme and holoenzyme forms include those that use vitamin Bx2, vitamin B, thiamin, and riboflavin-based cofactors. Enzymes that use niacin-based cofactors, folate, ascorbate, and vitamin K are not said to exist in apoenzyme and holocn-zyme forms. These enzymes bind their cofactors relatively weakly, and the cofactors behave in a manner similar to substrates. 

Vitamin B complex is the collective term for a number of water-soluble vitamins found particularly in dairy products, cereals and liver.Vitamin B (thiamine) is used by mouth for dietary supplement purposes and by injection in emergency treatment of Wernicke-Korsakoff syndrome. Vitamin B2 (riboflavin) is a constituent of the coenzyme FAD (flavine adenine dinucleotide) and FMN (flavine mononucleotide) and is therefore important in cellular respiration. Vitamin Be (pyridoxine) is a coenzyme for decarboxylases and transamination, and is concerned with many metabolic processes. Overdose causes peripheral neuropathy. It may be used medically for vomiting and radiation sickness and for premenstrual tension. Pyridoxine has a negative interaction with the therapeutic use of levodopa in parkinsonism by enhancing levodopa decarboxylation to dopamine in the periphery, which does not then reach the brain. The antitubercular drug isoniazid interferes with pyridoxine, and causes a deficiency leading to peripheral neuritis that may need to be corrected with dietary supplements. Vitamin B ... 

B (thiamine) Treats peripheral neuritis from alcoholism or beriberi... 

The ascorbic acid content in tamarind is very low and varies from 2-20 mg/lOOg (Lefevre, 1971 and Ishola et al, 1990, both cited in (5)). Tamarind frait pulp was reported to have a high content of vitamin B (thiamine, riboflavin and niacin) as well as a small amonnts of carotene and vitamin C (75). 

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