The present invention provides soluble cytochrome p450 reductase (CPR)
proteins from Candida sp. having an altered N-terminal region which
results in reduced hydrophobicity of the N-terminal region. Also provided
are host cells comprising the subject soluble CPR proteins. In addition,
the present invention provides nucleotide and corresponding amino acid
sequences for soluble CPR proteins and vectors comprising the nucleotide
sequences. Methods for producing a soluble CPR, for increasing production
of a dicarboxylic acid, and for detecting a cytochrome P450 are also
provided.