TABLE 3.

Pyruvate-dependent NADP reduction

Reaction componentsaNADP reduction (nmol/min)bSp act (U/mg protein)c
PFORFqrB
Complete (NADP)27 ± 20.269 ± 0.0213.5 ± 1
Complete (NAD)1.4 ± 0.20.014 ± 0.0020.7 ± 0.1
    −PFOR0.0300.015
    −FldA0.20.0020.10
    −FqrB0.30.0030
    −Pyruvate0.10.0010.05
    −CoA0.20.0020.10
    +NTZ (5 μM)16 ± 20.1608
    2× PFOR490.23324.5
    6× FqrB490.5443.8
    12× FqrB520.5782.1
    24× FqrB500.5561.3
Pseudoanaerobiosisd, complete (NADP)120.082.4
  • a Reaction components included flavodoxin (FldA), PFOR, and FqrB, and activities are computed in the absence (−) or presence (+) of components. The protein concentrations used were as follows: FldA, 9.5 μM; PFOR, 0.1 mg/ml; and FqrB, 0.002 mg/ml. The effect of different protein concentrations on enzymatic activity was determined at 2×, 6×, 12×, and 24× the indicated protein concentration.

  • b Relative activity of the complex. Values are means and standard deviations.

  • c The specific activity (units) for each protein (PFOR or FqrB) is in μmol min−1 mg protein−1. Values are means and standard deviations.

  • d Pseudoanaerobiosis indicates that no effort was made to sparge the cuvette of oxygen.