on pyridoxine or pyridoxamine as a sole source of carbon and nitrogen (1, 2). This transaminase contains no pyridoxal phosphate, and hence provides a simpler system for mechanistic studies than do the more complex, pyridoxal phosphate-containing transaminases. The enzyme binds pyridoxamine and pyridoxal with almost equal avidity; the latter is bound in part by an azomethine Iinkage to the e-ami...

Several pyridoxal-phosphate-dependent enzymes can convert the bound cofactor to pyridoxamine phosphate. This conversion may be an obligatory part of the normal catalytic sequence, as with transaminases, or may be an abnormal path, inactivating the enzyme. This conversion requires protonation of the C(4)' carbon of the cofactor, which has now been shown to proceed stereospecifically and with the...

Glucose. ...................... Sodium acetate (anhydrous). ... Salts A K~HPOI ..................... KHzPOr .................... Salts B MgSOa.7HzO. ................ MnS01.4H20. ............... NaCl ........................ FeSO,.7HzO .................. Adenine ....................... Guanine ....................... Uracil ......................... Thiamine chloride. ............. Pyridoxamine ...

Protein conjugates of pyridoxal have been used to elicit anti-vitamin B6 antibodies in rabbits. These antibodies have been incorporated into 2 homogeneous assays systems, a spin immunoassay, using a paramagnetic derivative of the vitamin as ligand, and a fluorescence enzyme immunoassay, using beta-galactosidase conjugated to vitamin B6 as the indicator molecule. These assay systems do not requi...

In previous studies it was found that: (a) aspartate aminotransferase increases the aspartate dehydrogenase activity of glutamate dehydrogenase; (b) the pyridoxamine-P form of this aminotransferase can form an enzyme-enzyme complex with glutamate dehydrogenase; and (c) the pyridoxamine-P form can be dehydrogenated to the pyridoxal-P form by glutamate dehydrogenase. It was therefore concluded (F...

Vitamin B 6 is an important vitamin for normal brain function. The metabolism of dietary vitamin B 6 to its active cofactor pyridoxal 5´-phosphate is described. The mechanism of action of pyridoxal 5´-phosphate is described, as are some important functions in the brain. The clinical features and biochemistry of three inborn errors of metabolism affecting brain pyridoxal 5´-phosphate concentrati...

Extracts of rabbit liver and brain are known (1, 2) to oxidize pyridoxine 5-phosphate to pyridoxal 5-phosphate much faster than they oxidize free pyridoxine to pyridoxal. Comparison of the two activities during limited purification indicated that different enzymes catalyzed the two reactions (1). Pogell (3) had shown previously that oxidation of pyridoxamine 5-phosphate was catalyzed by an enzy...

Accumulating evidence suggests that advanced glycation end products, generated as a consequence of facilitated carbonyl stress, are implicated in the development of a variety of diseases. These diseases include neurodegenerative illnesses, such as Alzheimer disease. Pyridoxamine is one of the 3 forms of vitamin B6, and it acts by combating carbonyl stress and inhibiting the formation of AGEs. D...