Pig plasma benzylamine oxidase is a protein containing cupric copper and pyridoxal phosphate. The pyridoxal phosphate is stably linked to the enzyme. Discrepancies in the numbers of active sites per molecule of enzyme are reported in the literature. This paper shows that the fully active pure enzyme contains 3 mol of pyridoxal phosphate per mol, whereas enzymes with a lower specific activity ar...

Yeast tRNAPhe and tRNATyr were reacted with the fluorescent reagent pyridoxal-5'-phosphate and the modified tRNAs were analysed with respect to the number and position of modified nucleosides and with respect to aminoacylation. a) Following the intrinsic fluorescence of pyridoxal-5'-phosphate, the treatment of tRNATyr with increasing amounts of pyridoxal-5'-phosphate revealed about 50 mol or re...

OBJECTIVE Intractable epilepsy is a serious neurologic problem with different etiologies. Decreased levels of pyridoxal phosphate in cerebral spinal fluid of patients with intractable epilepsy due to pyridoxine dependency epilepsy are reported. The aim of this study was to compare plasma pyridoxal 5´-phosphate level in patients with intractable and controlled epilepsy. MATERIALS & METHODS Thi...

The binding of rat liver glucocorticoid.receptor complexes to DNA-cellulose and nuclei has been studied after activation of the complexes by heating. Subsequent exposure to pyridoxal 5'-phosphate or pyridoxal markedly inhibited this binding. In one system 0.75 mM pyridoxal 5'-phosphate or 6.5 mM pyridoxal gave 50% inhibition. Pyridoxamine 5'-phosphate, pyridoxamine, and pyridoxine did not inhib...

Tritium-labeled pyridoxamine, pyridoxal S/-phosphate, and pyridoxine 5’-phosphate were prepared and administered intravenously to mice, and the distribution of isotope in liver and carcass between pyridoxine, pyridoxine 5’-phosphate, pyridoxal, pyridoxal S/-phosphate, pyridoxamine, and pyridoxamine 5’-phosphate was determined at different times after administration. The vitamin B6 forms were ex...

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...

Carbon-labeled glycolaldehyde prepared from [(14)C]serine was used to supply the nutritional requirement of a pyridoxineless auxotroph of Escherichia coli. Pyridoxal phosphate isolated from bacteria so grown was found to have incorporated the radioactive glycolaldehyde with little dilution. The radioactivity which was unincorporated into pyridoxal phosphate was recovered almost entirely in the ...

Pig muscle phosphoglucose isomerase modified with pyridoxal 5'-phosphate under conditions that cause at least 90% inactivation of its catalytic activity was found to incorporate about 1.5 eq of pyridoxal 5'-phosphate per subunit. After digestion with thermolysin, two pyridoxal 5'-phosphate-containing peptides were isolated and their amino acid sequences were determined to be Leu-Gly-pyridoxyl-L...

Hydrolysis of pyridoxal phosphate in plasma was demonstrated in patients with liver disease and other conditions with raised alkaline phosphatase, and this usually closely paralleled the alkaline phosphatase level, whether of liver or bone origin. The endogenous plasma pyridoxal phosphate was inversely related to the alkaline phosphatase, and plasma hydrolysis of pyridoxal phosphate may at leas...

The enzyme mitochondrial aspartate aminotransferase from beef liver is a dimer of identical subunits. The enzymatic activity of the resolved enzyme is restored upon addition of the cofactor pyridoxal 5-phosphate. The binding of 1 molecule of cofactor restores 50% of the original enzymatic activity, whereas the binding of a 2nd molecule of cofactor brings about more than 95% recovery of the cata...