?
 
erythrose-4-phosphate dehydrogenase This model represents the small clade of dehydrogenases in gamma-proteobacteria which utilize NAD+ to oxidize erythrose-4-phosphate (E4P) to 4-phospho-erythronate, a precursor for the de novo synthesis of pyridoxine via 4-hydroxythreonine and D-1-deoxyxylulose. This enzyme activity appears to have evolved from glyceraldehyde-3-phosphate dehydrogenase, whose substrate differs only in the lack of one carbon relative to E4P. Accordingly, this model is very close to the corresponding models for GAPDH, and those sequences which hit above trusted here invariably hit between trusted and noise to the GAPDH model (TIGR01534). Similarly, it may be found that there are species outside of the gamma proteobacteria which synthesize pyridoxine and have more than one aparrent GAPDH gene of which one may have E4PD activity - this may necessitate a readjustment of these models. Alternatively, some of the GAPDH enzymes may prove to be bifunctional in certain species. [Biosynthesis of cofactors, prosthetic groups, and carriers, Pyridoxine] |
Jiyao W et al.(2023). "The conserved domain database in 2023.",