Vitamin B, family

Riboflavin (vitamin B2) is found in liver, milk, meat, green vegetables, cereals and mushrooms. It is active in the form of two coenzymes, flavin mononucleotide and flavin adenine dinucleotide. As a coenzyme for proton transfer in the respiratory chain it is indispensable for energy-release from carbohydrates, lipids and proteins. Riboflavin deficiency only occurs in combination with deficiencies of other members of the vitamin B family. The symptoms of such deficiency consist of angular stomatitis, lesions of the cornea, dermatoses and normochromic normocytic anaemia. 

The Vitamin B Family Pyridoxine, Pyridoxal, and Pyridoxamine Dietary Requirements for B Vitamins... 

Biotin is a member of the vitamin B family and is an essential factor in the processes and maintenance of normal metabolism in human beings. It is an es-... 

Pyridine derivatives are precursors of many chemical products of medicinal, agricultural, and industrial importance. Pyridine itself is used not only as a solvent, but also as a starting material for pharmaceuticals, herbicides, insecticides, and fungicides. a-Picoline is a precursor for 2-vinylpyridine which is used in the production of an adhesive for textile tire cord. The major use of y-picoline is in the production of isonicotinic hydrazide, an antituberculosis agent. / -Picoline and 2-methyl-5-ethylpyridine are important intermediates in the production of two members of the vitamin B family, nicotinamide, and nicotinic acid (also known as vitamin B3). All this shows there is a substantial need for the production of picolines. The following text describes a novel route to a-picoline which might in the future lead to new processes. 

The formula of vitamin Bg was first published by Ohdake (1932) at the same time as several other scientific groups were working on the elucidation of the vitamin B family members. Gyorgy in 1934 first described vitamin Bg as the active rat pellagra prevention factor and subsequently named the substance pyridoxine due to its structural homology to pyridine (Gyorgy 1938). It was... 

A second common category of riboswitch is those that bind to the vitamin B family. A thiamine, vitamin Bi, riboswitch has been identified in the 5 -UTR of the thiA gene from A. oryzae that is involved in transcription of matnre mRNA," and the crystal strncture of the thiamine riboswitch from... 

ABC transporters involved in the uptake of siderophores, haem, and vitamin B]2 are widely conserved in bacteria and Archaea (see Figure 10). Very few species lack representatives of the siderophore family transporters. These species are mainly intracellular parasites whose metabolism is closely coupled to the metabolism of their hosts (e.g. mycoplasma), or bacteria with no need for iron (e.g. lactobacilli). In many cases, several systems of this transporter family can be detected in a single species, thus allowing the use of structurally different chelators. Most systems were exclusively identified by sequence data analysis, some were biochemically characterised, and their substrate specificity was determined. However, only very few systems have been studied in detail. At present, the best-characterised ABC transporters of this type are the fhuBCD and the btuCDF systems of E. coli, which might serve as model systems of the siderophore family. Therefore, in the following sections, this report will mainly focus on the components that mediate ferric hydroxamate uptake (fhu) and vitamin B12 uptake (htu). 

Historically choline, inositol and carnitine have been considered to be part of the vitamin B complex. However, for the general population there has been no demonstration of a dietary need for these agents and also for none of them has there been a therapeutic role established. Vitamins of the B family are found in many food ingredients like in yeast, in meat, in dairy products and also in eggs and grain cereals and separate vitamin B deficiencies are unlikely to occur. Excessive intake of these vitamins is eliminated in the urine because of the fact that they are water-soluble. 

Vitamins are divided into two major categories. They are fat-soluble (A, D, E and K) and water-soluble vitamins (B-complex and vitamin C). B complex vitamins include thiamine (Bi), riboflavin (B2), pantothenic acid (B3), niacin (B5), pyridoxine (Be), biotin (By), folic acid (B9), and cobalamin (Biy). Inositol, cholic and para-aminobenzoic acid are vitamin-like substances sometimes classified as part of the B complex, but no convincing evidence has been shown so far to be included as vitamins. All the fat-soluble vitamins and some B vitamins exist in multiple forms. The active forms of vitamin A are retinol, retinal and retinoic acid and vitamin D is available as ergocalciferol (D2) and cholecalciferol (D3). The vitamin E family includes four tocopherols and four tocotrienols but a-tocopherol being the most abundant and active form. The multiple forms of vitamins are interconvertible and some are interchangeable. 

Chemistry. The vitamin E family I )nsists of tocopherols and tocotrienols. There been considerable debate as to whether b RRR isomer is the only biologically active arm cf the vitamin. The vitamin of commerce a-tocopheroi, either as a racemic synthetic... 

The combination of hypophosphatemia, vitamin D resistance, osteomalacia, and rickets is seen in a number of syndromes (W24). These include (a) familial hypophosphatemic vitamin D-resistant rickets, a sex-linked, dominant disorder (P3), (b) familial vitamin D dependency, an autosomal recessive disorder due to la-hydroxylase deficiency (F19), and (c) nonfamilial hypophosphatemic osteomalacia (D9), considered by some workers (P3) to be a separate disease entity because of its late onset, its severity, and its lack of response to therapy. In addition, there are many inherited and acquired disorders which are associated with impairment of renal tubular reabsorption of phosphate, and these may be accompanied by hypophosphatemia, rickets, and relative vitamin D resistance. Serum alkaline phosphatase values in these disorders correlate poorly with the severity of the disease (A14) and with the response to therapy (E4, MclO, P7, S50). 

Stickler, G. B., Familial hypophosphatemic vitamin D resistant rickets. The neonatal period and infancy. Acta Paediat. Scand. 58, 213-219 (1969). 

Pantothenic add is stable at room temperature and is one of the most stable B family vitamins. It is not affected by storage at -20 °C for a month (Machlin 1991). The United States Pharmacopeia (USP) standard for pantothenic add is the (7(+)-enantiomer. Commercially available standards often are in the forms of sodium or calcium salts. The calcium salt of pantothenic acid (calcium pantothenate) is often used for fortification in the food and dietary supplement industries. 

Because most B family vitamins are more stable in acidic conditions than in basic conditions, extraction of these vitamins in acidic conditions is preferred. Since pantothenic acid itself is very stable at room temperature, extraction can be kept as simple as possible. Sonication with water or buffer at pH 2-3 is sufficient, even with the extraction of other B family vitamins in mind (Chen and Wolf 2007 Chen et al. 2009). After sonication, centrifugation and/or filtration for sample clean-up is usually sufficient. More complicated sample clean-up procedures, i.e. solid-phase extraction (SPE), are not usually necessary. 

This chapter has described a number of liposome-amplified competitive immunosensing systems for two members of the B family of vitamins, biotin and folic acid, in flow injection analysis (FIA), immunoaffinity column (lAC) and electrochemical formats. The use of the immunoaffinity sensors is... 

Vitamins are grouped into families based on their behavior (rather than their structure) each femily is designated with a letter. For example, vitamin B is a family of many compounds, each designated with a letter and a number (Bi, B2, B3, etc.). The table shows representative vitamins from several families ... 

B-complex vitamins A family of water-soluble vitamins that include thiamin, riboflavin, niacin, vitamin B6, folate, and vitamin B12. B-complex vitamins play central roles in metabolism, protein synthesis, and cell multiplication. 

It is noteworthy that vitamin C is the only member of the water-soluble group that is not a member of the B family. The two groups of vitamins exhibit the following several differences that distinguish them both chemically and biologically ... 

Dried Yeast, B.P.C. Dried yeast consists of unicellular fungi belonging to the family Saccharomycetaceae which have been dried so as to avoid decomposition of the vitamins present and which should be free from viable cells. It is a source of the vitamin B complex. For aneurine the determination follows the S.A.C, method outlined above using 1 g of sample. 

Para-amino benzoic acid (PABA) is considered to be in the B-complex vitamin family. The human body can make it from folic acid, since PABA forms the middle part of that vitamin ... 

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