rhPyridoxal Kinase, (50 ug)

Background: Pyridoxal Kinase/PDXK

Pyridoxal Kinase (PDXK) phosphorylates vitamin B6, a step required for the conversion of vitamin B6 to pyridoxal-5-phosphate (PLP), an important cofactor in intermediary metabolism (1). PLP is involved in many aspects of macronutrient metabolism, neurotransmitter synthesis, histamine synthesis, as well as hemoglobin synthesis, function, and gene expression (2). PLP generally serves as a co-enzyme for many reactions and can help facilitate decarboxylation, transamination, racemization, elimination, replacement and beta-group inter-conversion reactions. In particular, PLP also is needed for the enzymatic reaction governing the release of glucose from glycogen. Overall, there are over 160 PLP-dependent enzymes, corresponding to ~4% of all known enzymatic activities (3). The classic clinical syndrome for B6 deficiency is a seborrhoeic dermatitis-like eruption, atrophic glossitis with ulceration, angular cheilitis, conjunctivitis, intertrigo, accompanied by neurologic symptoms of somnolence, confusion, and neuropathy (4).The neurotoxic effects of ophylline and ginkgotoxin are caused by their inhibitory activity against human PDXK (3, 5). Genetic variations of PDXK are associated with Parkinson disease, since PLP is involved in the biosynthesis of dopamine, a neurotransmitter linked to the disease characteristics such as motor and movement disorders (6). PDXK is also a potential drug target in the African trypanosomiasis (7). PDXK is a cytoplasmic enzyme and probably acts as a homodimer in vivo (8). The enzymatic activity of recombinant human CHKB is measured using a phosphatase-coupled method (9).