Purification and characterisation of a non-plant myrosinase from the cabbage aphid Brevicoryne brassicae (L.)

Plant myrosinases and glucosinolates constitute a defence system in crucife rous plants towards pests and diseases. We have purified for the first time a non-plant myrosinase from the cabbage aphid Brevicoryne brassicae (L.) t o homogeneity. The protein was N-terminally blocked and protease (trypsin a nd lys c) degradation gave peptides of which five were sequenced. The prote in is a dimer with subunits of mass 54 kDa+/-500 Da. Western blot analysis with an anti-aphid myrosinase antibody showed a strong cross reaction with a protein extract from the Brassica specialist, B. brassicae. The anti-aphi d myrosinase antibody does not cross react with plant myrosinase neither do es an anti-plant myrosinase antibody cross react with aphid myrosinase. (C) 2001 Elsevier Science Ltd. All rights reserved.