Vein Patterning 1-encoded progesterone 5β-reductase: Activity-guided improvement of catalytic efficiency

► Vein Patterning 1-encoded progesterone 5β-reductases are substrate-promiscuous enone reductases. ► Catalytically 'strong' and 'weak' progesterone 5β-reductases were identified. ► An activity-guided screen was used to propose 'hot spots' for site-directed mutagenesis. ► Catalytic efficiency of Vein Patterning 1-encoded progesterone 5β-reductase was improved. ► Amino acid residues responsible for progesterone 5β-reductase 'weakness' were substituted.