Pyridoxal phosphate formula

Pyridoxal phosphate (Formula 2.12) and pyridox-amine (Formula 2.13), derived from it, are designated as vitamin 65 (cf. 6.3.3) and are essential ingredients of food ... 

Isoniazid (isonicotinic acid hydrazide), a drug frequently used to treat tuberculosis, can induce a B6 deficiency by forming an iiactive derivative with pyridoxal phosphate. Dietary supplementation with B is, thus, an adjunct to isoniazide treatment. Otherwise, cletary deficiencies in pyridoxine are rare but have been observed in newborn infants fed formulas low in vitamin B6, in women taking oral contraceptives, and in alcoholics. 

Pyridoxal phosphate, PalP the coenzyme form of Vitamin Bj (see Vitamins for formula of PalP and related compounds). Af, of PalP 247.1. PalP is stable in aqueous solution when kept refrigerated and pro-teeted from light It is particidarly sensitive to photodecomposition in the solid state and in alkaline solution. PalP plays an important central role in amino acid metabolism, acting as the coenzyme in many different metabolic conversions of amino acids. It is formed from pyridoxal by a Mg -dependent kinase reaction pyridoxal + ATP -> pyridoxal 5-phosphate + ADP. With amines and amino acids, PalP forms SchifTs bases (azomethines). The substrate of a pyrid-... 

Chemistry— Vitamin B-6 is found in foods in three forms which are readily interconvertible—pyridoxine, pyridoxal, and pyridoxamine. Also vitamin B-6 is found in physiological systems in the forms of pyridoxal phosphate and pyridoxamine phosphate. The structural formulas of the three naturally occurring free forms of these compounds are given in Fig. V-30. 

The mechanism of this enzymic reaction, catalyzed by pyridoxal phosphate, has been discussed above as pathway b (Section 4). The net result is the production of CO2 and a primary amine, whose formula can easily be derived from the amino acid which was decarboxylated. Amines of this type are called biogenic amines (Guggenheim) many of them possess a strong pharmacologic effect, and others are important as precursors of hormones and as components of coenzymes and other active substances. 

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

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