Xyloglucan Endotransglucosylase - Xyloglucan Complex in Golgi

Abstract

Xyloglucan endotransglucosylase (XET) is a cell wall enzyme capable of cleaving and reconnecting xyloglucan molecules. Integration of whole xyloglucan and its oligosaccharides into pea cell wall by XET causes suppression and acceleration of cell elongation, respectively. The immunohistochemical observation showed that XET could coexist with xyloglucan in Golgi before the integration of xyloglucan-XET complex to the cell wall in the elongating region of pea stem. In pulse-chase experiment the molecular mass of xyloglucan increased from 8.8 kDa to 110 kDa by endotransglucosylation when 230 kDa xyloglucan was supplied. We propose that the XET binds to non reducing end of xyloglucan in trans Golgi to form enzyme-acceptor complex.