Pyndoxal phosphate

Pyndoxal phosphate is also a cofactor for transamination reactions, In these reactions, an amino group is transferred from an amino acid to an or-keto acid, thus founing a new amino acid and a new or-keto acid, Transamination reactions are important for the synthesis of amino acids from non-protein metabolites and for the degradation of amino acids for energy production. Since pyridoxal phosphate is intimately involved ill amino add metabolism, the dietary requirement for vitamin B6 increases as the protein content of the diet increases. 

Figure 24.16 Structure of tryptophan synthase. The structure of the complex formed by one a subunit and one (3 subunit. Notice that pyndoxal phosphate (PLP) is bound deeply inside the (3 subunit, a considerable distance from the a subunit. [Drawn from IBKS.pdb.]...

Massieu G H, Tapia R, Pasantes H., and Orteg B. G (1964) Convul-sant effect of L-glutamic acid -hydrazine by simultaneous treatment with pyndoxal phosphate. Biochem Pharmacol 13, 118-120... 

Bis-Pyndoxal Tetraphosphate. A second class of bifunctional reagents, described in 1988, involves two pyridoxal groups linked by phosphates of different lengths (89). As shown in Table 4, the yield of intramolecularly cross-linked hemoglobin increases dramatically with increasing length of the phosphate backbone. It is beheved that the site of reaction of (bis-PL) is between the amino-terminal amino group of one P-chain and the... 

In plants, the vilamin is present as pyridoxol-5-phosphate, pyndoxal-5-phosphate, or pyridoxamine-phosphate. In plants, production sites are found in fungi, cereal germ, and seeds. 

The Aeromonas and Pseudomonas enzymes have been studied in detail. Both enzymes are very sensitive to sulfhydryl and carbonyl inhibitors and possess 4 moles of pyndoxal 5 -phosphate bound in aldimine linkages to -amino groups of lysine residues. They nave similar substrate specificities and, in... 

Vitamin B-6, in its coenzyme forms, usuaBy as pyridoxal phos phaie but sometimes as pyndox amine phosphate, is involved m a large number of physiologic functions. particularly ... 

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