The coupling of catharanthine and vindoline to form 3',4'-anhydrovinblastine by haemoproteins and haemin.

The enzymic coupling of catharanthine and vindoline can be performed with plant peroxidases in a reaction which yields 3',4'-anhydrovinblastine (AVLB) as the major product. This has led to an investigation of other sources of peroxidase activity and haem. High levels of AVLB were obtained using microperoxidase (haem-undecapeptide) and haemin, and lower yields were also detected with lactoperoxidase, cytochrome C, and haemoglobin. The activity with haemin and microperoxidase has been optimized and it is concluded that, in comparison with horseradish peroxidase, these systems provide an improved means of coupling.