TABLE I.

ABA 8′-hydroxylase acitivity of the recombinant CYP707A3 microsomes

Assay conditionsABA 8′-Hydroxylase Activity PA + 8′-OH-ABAbRelative Activity
ng%
Completea197 ± 15100
    - NADPHn.d.c-
    - NADPH + 100 μM NADHn.d.-
    + AR1 (NADPH-P450 reductase)338 ± 6172
    +100 μM cytochrome cn.d.-
    - (+)-ABA + 100 μM (-)-ABAn.d.-
  • a The complete reaction mixture contained 50 mm potassium phosphate (pH 7.25), 50 μg/mL recombinant CYP707A3 microsomes, 100 μm NADPH, and 100 μm (+)-ABA.

  • b Reactions were initiated by addition of NADPH and carried out in the reaction mixture at 30°C for 10 min. The amounts of the reaction products (PA and 8′-OH-ABA) were estimated as the relative response to standard PA. Values are mean ± sd of three separate determinations.

  • c Not detected. The detection limit for the total amounts of PA and 8′-OH-ABA in the reaction mixtures was 50 ng.