Pyridoxine acids

Vitamin deficiency may produce seborrhea-like symptoms. In addition, tryptophan catabolism is disturbed kynurenine, 3-hydroxy-kynurenine, and xanthurenic acid appear in urine. Excess pyridoxine is oxidized to pyridoxinic acid (like pyridoxal, but with a carboxyl in place of the aldehyde group) and excreted. 

An example of this methodology was its use in the synthesis of vitamin Be, pyridoxine 12. Cycloaddition of oxazole 9, prepared from ethyl A-acetylalanate and P2O5, with maleic anhydride initially gave 10. Upon exposure to acidic ethanol, the oxabicyclooctane system fragments to afford pyridine 11. Reduction of the ester substituents with LiAlIU generated the desired product 12. 

Most amino acids lose their nitrogen atom by a transamination reaction in which the -NH2 group of the amino acid changes places with the keto group of ct-ketoglutarate. The products are a new a-keto acid plus glutamate. The overall process occurs in two parts, is catalyzed by aminotransferase enzymes, and involves participation of the coenzyme pyridoxal phosphate (PLP), a derivative of pyridoxine (vitamin UJ. Different aminotransferases differ in their specificity for amino acids, but the mechanism remains the same. 

In terms of amino acids bacterial protein is similar to fish protein. The yeast s protein is almost identical to soya protein fungal protein is lower than yeast protein. In addition, SCP is deficient in amino acids with a sulphur bridge, such as cystine, cysteine and methionine. SCP as a food may require supplements of cysteine and methionine whereas they have high levels of lysine vitamins and other amino acids. The vitamins of microorganisms are primarily of the B type. Vitamin B12 occurs mostly hi bacteria, whereas algae are usually rich in vitamin A. The most common vitamins in SCP are thiamine, riboflavin, niacin, pyridoxine, pantothenic acid, choline, folic acid, inositol, biotin, B12 and P-aminobenzoic acid. Table 14.4 shows the essential amino acid analysis of SCP compared with several sources of protein. 

In general, pyridoxamine and pyridoxin are more stable than pyridoxal. All vitamers are relatively heat-stable in acid media, but heat labile in alkaline media. All forms of vitamin B6 are destroyed by UV light in both neutral and alkaline solution. The majority of vitamin B6 in the human body is stored in the form of pyridoxal phosphate in the muscle, bound to glycogen phos-phorylase. 

CnHijNjO, 80573-04-2) see Balsalazide sodium DL-(l-carboxyethyl)oxamic acid diethyl ester (C7H15NO5 23460-73-3) see Pyridoxine... 

C5H4N2O 1003-52-7) see Pyridoxine 2-cyano-3-methyl-2-pentenoic acid ethyl ester (C HijNOj 759-51-3) see Ethosuxiinide... 

C4H5NO 693-93-6) see Pyridoxine 4-methyloxazole-S-carboxamide (C5H4N2O2 4866-00-6) see Pyridoxine 2-methyi-4-(oxiranylmethoxy)-ltf-indole (Ci.H.jNOa 62119-47-5) see Bopindolol Mepindolol (2S-7ranj)-(2-methyl-4-oxo-3-azetidinyl)carbamic acid 1,1-dimelhylethyl ester (C9H14N2O3 80582-03-2) see Aztreonam... 

Pyridoxal 157,158,253 Pyridoxamine 253 Pyridoxine 253 Pyrimidines 266,438, 439 Pyrocatechol see 1,2-Dihydroxybenzene I ocatecholsulfophthalein 398 I ocatechol violet reagent 398 Pyrolysis of organic compounds 92, 96 a,y-Pyrone derivatives 288 Pyrrole alkaloids 66 Pyrrole derivatives 266, 269, 270 Pyruvic acid 426... 

Purpuric acid lb 174 Pyrazolidine derivatives la 426 3,5-Pyrazolidindione derivatives lb 20 Pyrazolinone derivatives lb 277 Pyrazolin-5-one derivatives lb 327,329 Pyrazone lb 332 Pyrene lb 379 PyrethrinI lb 18 Pyrethrin II lb 18 Pyrethroids lb 86,87 Pyrethroid insecticides la 359 Pyridine alkaloids la 66 lb 279 Pyridine derivatives lb 119,244 Pyridinium carbinols lb 65 Pyridinium glycols lb 65 Pyridoxal la 157,158,253 Pyridoxamine la 253 Pyridoxine la 253... 

The water-soluble vitamins comprise the B complex and vitamin C and function as enzyme cofactors. Fofic acid acts as a carrier of one-carbon units. Deficiency of a single vitamin of the B complex is rare, since poor diets are most often associated with multiple deficiency states. Nevertheless, specific syndromes are characteristic of deficiencies of individual vitamins, eg, beriberi (thiamin) cheilosis, glossitis, seborrhea (riboflavin) pellagra (niacin) peripheral neuritis (pyridoxine) megaloblastic anemia, methyhnalonic aciduria, and pernicious anemia (vitamin Bjj) and megaloblastic anemia (folic acid). Vitamin C deficiency leads to scurvy. 

Be Pyridoxine, pyridoxal, pyridoxamine Coenzyme in transamination and decarboxylation of amino acids and glycogen phosphorylase role in steroid hormone action Disorders of amino acid metabolism, convulsions... 

Six compounds have vitamin Bg activity (Figure 45-12) pyridoxine, pyridoxal, pyridoxamine, and their b -phosphates. The active coenzyme is pyridoxal 5 -phos-phate. Approximately 80% of the body s total vitamin Bg is present as pyridoxal phosphate in muscle, mostly associated with glycogen phosphorylase. This is not available in Bg deficiency but is released in starvation, when glycogen reserves become depleted, and is then available, especially in liver and kidney, to meet increased requirement for gluconeogenesis from amino acids. 

Pantothenic acid is present in coenzyme A and acyl carrier protein, which act as carriers for acyl groups in metabolic reactions. Pyridoxine, as pyridoxal phosphate, is the coenzyme for several enzymes of amino acid metabolism, including the aminotransferases, and of glycogen phosphorylase. Biotin is the coenzyme for several carboxylase enzymes. 

Rice bran is the richest natural source of B-complex vitamins. Considerable amounts of thiamin (Bl), riboflavin (B2), niacin (B3), pantothenic acid (B5) and pyridoxin (B6) are available in rice bran (Table 17.1). Thiamin (Bl) is central to carbohydrate metabolism and kreb s cycle function. Niacin (B3) also plays a key role in carbohydrate metabolism for the synthesis of GTF (Glucose Tolerance Factor). As a pre-cursor to NAD (nicotinamide adenine dinucleotide-oxidized form), it is an important metabolite concerned with intracellular energy production. It prevents the depletion of NAD in the pancreatic beta cells. It also promotes healthy cholesterol levels not only by decreasing LDL-C but also by improving HDL-C. It is the safest nutritional approach to normalizing cholesterol levels. Pyridoxine (B6) helps to regulate blood glucose levels, prevents peripheral neuropathy in diabetics and improves the immune function. 

FIGURE 10.2 Structural formula of vitamin and related compounds. 1 — pyridoxine, 2 — pyridoxal, 3 — pyridoxamine, 4 — 4-pyridoxic acid 5 — pyridoxal-5 -phosphate. 

Solvent System (v/v) Pyridoxal Pyridoxine Pyridoxic Acid Pyridoxic Acid Lactone Pyridoxamine Pyridoxal Phosphate... 

The steroids aldosterone, cortisone, cortisol, 11-P-hydroxyandrostenedione, corticosterone, and rostenedione, 11-desoxycorticosterone, 17-hydroxy-progesterone, and progesterone have been performed on Ultrasphere ODS using methanokwater.19 Ranitidine N-[2-[[[5-[(dimethylamino)methyl]-2-furanyl]-methyl]thio]ethyl]-N1-methyl-2-nitro-l,l-ethenediamine has been separated using a p-Bondapak C18 column operated with acetoni-trile methanol water buffered with triethylamine phosphate.117 Pyridoxal-5 -phosphate and other B6 vitamers, including pyridoxamine phosphate, pyri-doxal, pyridoxine, and 4-pyridoxic acid, were separated as bisulfite adducts... 

Water-soluble vitamins removed by hemodialysis (HD) contribute to malnutrition and vitamin deficiency syndromes. Patients receiving HD often require replacement of water-soluble vitamins to prevent adverse effects. The vitamins that may require replacement are ascorbic acid, thiamine, biotin, folic acid, riboflavin, and pyridoxine. Patients receiving HD should receive a multivitamin B complex with vitamin C supplement, but should not take supplements that include fat-soluble vitamins, such as vitamins A, E, or K, which can accumulate in patients with renal failure. 

The water-soluble vitamins generally function as cofactors for metabolism enzymes such as those involved in the production of energy from carbohydrates and fats. Their members consist of vitamin C and vitamin B complex which include thiamine, riboflavin (vitamin B2), nicotinic acid, pyridoxine, pantothenic acid, folic acid, cobalamin (vitamin B12), inositol, and biotin. A number of recent publications have demonstrated that vitamin carriers can transport various types of water-soluble vitamins, but the carrier-mediated systems seem negligible for the membrane transport of fat-soluble vitamins such as vitamin A, D, E, and K. 

---