A/C Enzymatic B6 Assays


510k: 111260

Intended Use:the quantitative in vitro diagnostic determination of pyridoxal 5-phosphate (PLP, vitamin B6) in EDTA-Plasma. The device will be used to monitor PLP concentrations in plasma for aid in diagnosis of vitamin B6 deficiency. The A/C Enzymatic Vitamin B6 Assay is for in vitro diagnostic use only.

Principle of the A/C B6 Assay

The assay is based on a PLP-dependent recombinant homocysteine-α,γ-lyase (rHCYase), which is prepared in the apo-enzyme form by stripping off the cofactor PLP (vitamin B6). The restoration of enzymatic activity by reconstitution of the holoenzyme depends on the amount of PLP in the plasma bound to apo-enzyme and production of H2S by the enzymatic reaction. H2S combines with DBPDA, the combination of which forms chromophore. The absorbance of this compound is read at 675 nm (660- -680nm).


PLP in Plasma

apo -enzyme


Homocysteine    α-Ketobutyrate + H2S + NH3



Absorbance Reader  (660-680 nm))


Fig. 2. Correlation of A/C Enzymatic B6 Assay with ALPCO B6 REA