The nature of the taro acridity factor

The acridity in Araceae species was not apparently due to the calcium oxala te raphides. Some irritant on the raphide surface caused the acridity, with the raphides apparently functioning to carry the acridity factor. Methanol and methylene chloride extracts from purified raphides did not show any co mpounds in GC-mass spectrometry (MS) analysis that could be regarded as acr id. The data suggested that a 26 kDa protein, possibly a cysteine proteinas e, was the active factor. There were a few other uncharacterized protein ba nds associated with the raphides that could also be involved. Some amino ac id sequence data for the 26 kDa protein was obtained. (C) 1999 Elsevier Sci ence B.V. All rights reserved.