Abstract: Pyridoxal Kinase (PLK) is the key enzyme in VB₆ metabolism. The crude solution of PLK enzyme was directly extracted from tea plant, after depositing and dialysing with ammonia sulfate by using the phenylhydrazine derivative method to assay the activity of the PLK and its properties. Results showed that the addition of 100%(m/m) PVPP of the fresh tea leaves extraction the PLK could get the best results. The purified tea PLK was enriched by 4.0 fold and its specific activity was 0.737 nmol/(min·mg protein). The requirement of divalent ion for catalysis was mandatory, Zn²⁺ was the most efficient ion for catalysis; the optimum temperature and pH of the enzyme were 60℃ and 6.0, respectively. Under optimal conditions, the Km values for pyridoxal and its reactive substrate ATP were 19.3 μmol/L and 53 μmol/L.

Key words: tea, vitamin B₆, pyridoxal kinase, analysis of activity