Biotin and thiamine

The more complex sulphur requirements of the marine animals are met largely by cysteine, cystine, methionine, biotin, and thiamine (Young and Maw, 1958) (Fig. 4). Cysteine is a component of the tripeptide glutathione and a precursor of taurine. Methionine is as an essential amino acid involved in biosynthesis of proteins, creatine and adrenaline. Adenosylmethionine is considered to be the active part in transmethylation, e.g. of choline. Methionine is part of the pathways to homocysteine, cystathionine and methylthioadenosine (Young and Maw, 1958). Various organisms convert cysteine and/or cystine into mercapturic acids, cysteine sulphinic acid, and thiazolidine derivatives (Zobell, 1963). 

Most of the sulphur in the animal body occurs in proteins containing the amino acids cystine, cysteine and methionine. The two vitamins biotin and thiamin, the hormone insulin and the important metabolite coenzyme A also contain sulphur. The structural... 

Sulfur Component uf the vitamins biotin and thiamin component of coenzyme A ICoAI. 

Schopfer 34, 35) reported that biotin was essential for E. ashbyii and that inodtol and thiamine acted as supplementary factors however, Dulaney and Grutter 36) and Yaw 37) demonstrated an absolute requirement for inodtol but not for biotin and thiamin. It has been suggested by Hickey 38) that these iqiparently contradictory requirements may be attributed to variations in stnuns of E. asKbyii used by the different authors. 

Lyases and Synthases are enzymes which catalyze the cleavage of a compound into two fragments or, in reverse, which catalyze the joining of two substances to form a third (synthases). The latter reaction is frequently equivalent to a group transfer. While it is still possible to draw up boundaries for the classification of the enzymes in this respect, for the coenzymes it ceases to be possible. Numerous groups activated by coenzymes participate in the reactions of synthases, as e.g. acetyl-CoA, carboxy-biotin, and thiamine-bound active aldehyde. 

One of the organisms fulfills the need for a growth requirement by the other, for example, vitamin requirements of one organism that is provided by the other. Examples are provided by biotin in cocultures of Methylocystis sp. and Xanthobacter sp. (Lidstrom-O Connor et al. 1983), and thiamin in cocultures of Pseudomonas aeruginosa and an undefined Pseudomonas sp. that degraded the phosphonate herbicide glyphosate (Moore et al. 1983). 

Vitamins such as thiamin, biotin, and vitamin Bj2 are often added. Once again, the requirements of anaerobes are somewhat greater, and a more extensive range of vitamins that includes pantothenate, folate, and nicotinate is generally employed. In some cases, additions of low concentrations of peptones, yeast extract, casamino acids or rumen fluid may be used, though in higher concentrations, metabolic ambiguities may be introduced since these compounds may serve as additional carbon sources. 

In an investigation of the water-soluble vitamins in human skin,71 it was found that 15 individuals showed relatively small ranges (less than 2-fold) for vitamin B12, folic acid, and biotin about 2-fold ranges in the cases of riboflavin, niacin, and thiamine about a 4-fold range in the case of ascorbic acid, and more than a 5-fold range in the case of pantothenic acid. In another study72 it was found that the total choline content of normal skin varied in four individuals over approximately a 10-fold range 127 to 1200 ig. per gm. The variation in the free choline in the same individuals was relatively small. 

Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin Bg, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington National Academy, 1998. 

As aromatic compounds have been exhausted as building blocks for life science products, A-heterocyclic structures prevail nowadays. They are found in many natural products, such as chlorophyll hemoglobin and the vitamins biotin (H), folic acid, niacin (PP), pyridoxine HCl (Be), riboflavine (B2), and thiamine (Bi). In life sciences 9 of the top 10 proprietary drugs and 5 of the top 10 agrochemicals contain A-heterocycIic moieties (see Tables 11.4 and 11.7). Even modern pigments, such as diphenylpyrazolopyrazoles, quinacri-dones, and engineering plastics, such as polybenzimidazoles, polyimides, and triazine resins, exhibit an A-heterocydic structure. 

Vitamins are chemically unrelated organic compounds that cannot be synthesized by humans and, therefore, must must be supplied by the diet. Nine vitamins (folic acid, cobalamin, ascorbic acid, pyridoxine, thiamine, niacin, riboflavin, biotin, and pantothenic acid) are classified as water-soluble, whereas four vitamins (vitamins A, D, K, and E) are termed fat-soluble (Figure 28.1). Vitamins are required to perform specific cellular functions, for example, many of the water-soluble vitamins are precursors of coenzymes for the enzymes of intermediary metabolism. In contrast to the water-soluble vitamins, only one fat soluble vitamin (vitamin K) has a coenzyme function. These vitamins are released, absorbed, and transported with the fat of the diet. They are not readily excreted in the urine, and significant quantities are stored in Die liver and adipose tissue. In fact, consumption of vitamins A and D in exoess of the recommended dietary allowances can lead to accumulation of toxic quantities of these compounds. 

Thiamine, biotin and pyridoxine (vitamin B) coenzymes are grouped together because they catalyze similar phenomena, i.e., the removal of a carboxyl group, COOH, from a metabolite. However, each requires different specific circumstances. Thiamine coenzyme decarboxylates only alpha-keto acids, is frequently accompanied by dehydrogenation, and is mainly associated with carbohydrate metabolism. Biotin enzymes do not require the alpha-keto configuration, are readily reversible, and are concerned primarily with lipid metabolism. Pyridoxine coenzymes perform nonoxidative decarboxylation and are closely allied with amino acid metabolism. 

The desugaring of cane juice concentrates the heat- and alkali-stable vitamins in the final molasses. Even after this accumulation, only myo-inositol may have reached the level of minimum dietary requirements.109 Niacin, pantothenic acid and riboflavin are also present in significant quantities109 the thiamine, pyridoxin, pantothenic acid, biotin and folic acid contents of molasses have been estimated by bioassay.110 111 The biotin content of Hawaiian and Cuban molasses was 2.1 and 1.7 gammas per gram, respectively.119 The antistiffness factor (closely related to stigmasterol) has been found in cane molasses.88 89 The distillery slop from the yeast fermentation of molasses is marketed as a vitamin concentrate this product also contains vitamins originating in the yeast. 

Meats, poultry, fish, and beans provide thiamin, riboflavin, niacin, pyridoxine, pantothenic acid, biotin, and vitamin Bi2. 

Fermentation Conditions All juices had additions prior to fermentation in order to eliminate deficiencies from being a factor in hydrogen sulfide formation. These included 120 mg N/L in the form of diammonium phosphate (DAP), 50 mg/L S02, 75 ug/L pantothenate, 2 ug/L biotin and 75 ug/L thiamin. All fermentations were inoculated widi 240 mg/L of active dry wine yeast (Fermivin), that had been reactivated in 35°C water. All fermentations were conducted in duplicate at 25°C, in temperature controlled, constantly stirred (100 rpm), fermentors (Applikon) using 500 mL of white juice or 300 mL juice of red juice plus the corresponding amount of skins and seeds. 

National Academy of Sciences Food and Nutrition Board, Dietary reference intakes for thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin and choline. National Academy Press, Washington D.C., 1998, pp. 309 22. 

Three NifS-like proteins, IscS, CSD, and CsdB, from E. coli catalyse the removal of sulfur and selenium from L-cysteine and L-selenocysteine, to form L-alanine. These enzymes are proposed to function as sulfur-delivery proteins for iron-sulfur clusters, thiamin, 4-thiouridine, biotin, and molybdopterin. Mihara et alP have reported evidence that a strain lacking IscS is incapable of synthesiz-... 

The potential of PBI LC-MS in the analysis of various vitamins was explored by Careri et al. [99-100]. The fat-soluble vitamins A, D, and E were analysed in food and multivitamin preparations [99]. Absolute detection limits in SIM mode were 0.6-25 ng after fast leversed-phase separation using a 97% aqueous methanol as mobile phase. Mass spectra in El, positive-ion and negative-ion Cl were obtained and discussed. The mass-spectral and quantitative performance of PBI LC-MS in the analysis of eleven water-soluble vitamins was also explored [100]. Detection limits were determined in SIM mode under positive-ion Cl, and were below 15 ng for ascorbic acid, nicotinamide, nicotinic acid, and pyridoxal, around 100 ng for dehydroascorbic acid, panthothenic acid, and thiamine, and above 200 ng for biotin, pyridoxamime, and pyridoxine. Riboflavine was not detected. 

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