Disease relevance of PDXK

• Crystal structure of pyridoxal kinase from the Escherichia coli pdxK gene: implications for the classification of pyridoxal kinases [1].

High impact information on PDXK

• Results have shown that pyridoxal kinase, as an enzyme obeying random sequential kinetics in catalysis, does not possess a lid shape structure common to all kinases in the ribokinase superfamily [2].
• The unfolding of brain pyridoxal kinase by guanidinium HCl has been investigated at equilibrium [3].
• This suggests that phosphorylation of pyridoxal can occur via direct transfer of the phosphoryl group between the bound substrates at the active site of pyridoxal kinase [4].
• 4-Benzoylbenzoic acid inhibits pyridoxal kinase activity competitively with respect to pyridoxal [5].
• Crystals of pyridoxal kinase from sheep brain have been grown from solutions of ammonium sulfate or Na+/K+ phosphate [6].

Biological context of PDXK

• The amino acid sequence of the sheep brain enzyme shows high similarity (86.2% identity) with the human pyridoxal kinase recently reported [Hanna, Turner, and Kirkness, (1997), J. Biol. Chem. 272, 10756-10760] [7].
• Arrangement of the substrates at the active site of brain pyridoxal kinase [4].

Associations of PDXK with chemical compounds

• Binding studies showed that 4-benzoylbenzoic acid bound to pyridoxal kinase at a 1:1 molar ratio and with a dissociation constant (Kd) of 5.9 x 10(-5) M [5].
• Affinity labeling of pyridoxal kinase with adenosine polyphosphopyridoxal [8].
• The presence of a tyrosine residue at the active site of pyridoxal kinase was confirmed by reaction with tetranitromethane [5].
• Pyridoxal kinase is inactivated by preincubation with the affinity label reagent adenosine tetraphosphate pyridoxal (AP4-PL) at a mixing molar ratio of 5:1 AP4-PL contains structural features of the substrates pyridoxal and ATP [8].
• Pyridoxal kinase, a member of the ribokinase superfamily, catalyzes the ATP-dependent phosphorylation reaction of vitamin B6 and is an essential enzyme in the formation of pyridoxal-5'-phosphate, a key cofactor for over 100 enzymes [9].

Other interactions of PDXK

• Binding of aspartate aminotransferase (apoenzymes) to pyridoxal kinase tagged with a fluorescent probe was detected by emission anisotropy measurements at pH 6.8 (150 mM KCl) [10].

Analytical, diagnostic and therapeutic context of PDXK

• Crystallization and preliminary X-ray studies of pyridoxal kinase from sheep brain [6].
• Physical interactions between pyridoxal kinase and aspartate aminotransferase were detected by means of emission anisotropy and affinity chromatography techniques [10].
• A compact intermediate on the unfolding pathway of pyridoxal kinase could not be detected by the method of denaturant gel filtration [3].
• Unfolding of pyridoxal kinase was monitored by circular dichroism and fluorescence spectroscopy [3].
• Further results obtained from electron microscopy, using a negative staining technique, provide evidence that pyridoxal kinase exists as a dispherical subunit structure [11].

References