An NADPH-dependent non-enzymatic cytochrome c reductant in cotyledons of bean

An active, thermostable cytochrome c reductant has been found in the cytosol of Phaseolus vulgaris cotyledons. This reducing activity is enhanced in the presence of NADH or NADPH and is attributable to a molecule of low molecular mass that is non-proteinaceous. The existence of this soluble reductant confounds measurements of enzymes that involve the use of exogenous electron acceptors and cofactors unless it is recognized and distinguished from true enzymatic activity.