Induction of tyrosine aminotransferase by pyridoxine in Drosophila hydei.

Salivary glands incubated in various concentrations of pyridoxine (Vitamin B6) show increasing tyrosine aminotransferase (TAT) activity at concentrations up to 10(-5) M and then decreasing activity up to 10(-2) M but in all cases the activity is greater than that of the controls. This increase in activity is demonstrable for up to 6 h, the longest period tested, and is dependent on the synthesis of new mRNA. A similar increase in TAT activity is observed in salivary glands subjected to heat shock. Antibodies prepared against purified tyrosine aminotransferase precipitate a peptide of the same molecular weight (40 KD) as that induced by pyridoxine.