反应详情

Absorbance Spectrum of Quinoid-6,6-Me2PH2Generated by Phenylalanine Hydroxylase. Spectra were taken of the q-6,6-Me2PH2 synthesized enzymatically from 6,6-Me2PH4, and a comparison made with the chemically produced compound. The spectrophotometer was baseline corrected with sample and reference cuvettes containing all of the reaction components (0.1M Tris·HCl, pH 7.4, 4 mM phenylalanine, 2500 units catalase, 0.3 unit phenylalanine hydroxylase) except pterin in a total volume of 0.99 ml. 6,6-Me2PH4 (10 μl of 10 mM) was then added to the sample and distilled H2O (10 μl) to the reference cuvette. Scanning was begun immediately and spectra taken at 2 minute intervals. The formation of q-6,6-Me2PH2 was complete within 4 minutes. After correction for tyrosine formed and phenylalanine consumed, the spectrum was within 3% of that produced by Br2 oxidation of 6,6-Me2PH4 (FIGURE).

1. additioncontaining all
2. distillationdistilled H2O (10 μl) to the reference cuvette
3. waitThe formation of q-6,6-Me2PH2 was complete within 4 minutes