1.1.1.405 K386A mutant impaired for reduction of D-ribulose. Equimolar mixtures of mutants K386A and R18A are efficient for bifunctional catalysis 645254 1.1.1.405 R18A mutant impaired for cytidylyl transfer. Equimolar mixtures of mutants K386A and R18A are efficient for bifunctional catalysis 645254