Hemicellulose xyloglucan derivatives

Free arabinose and galactose, which are often associated with hydroxyproline-rich proteins, are found in the free space of cell walls (132). Levels of proteins and free hydroxyproline are increased by ethylene treatment of pea (Fisum sativa) stem segments. However, the total amount of hydroxyproline in ethanol-insoluble polymers after extraction of the free space with water and Ca was not influenced by ethylene. Terry et al. (132) propose that the response to ethylene, which is now known to be derived from methionine, can be divided into two components. One requires changes in cellulose microfibrils of the cell wall, which result in reorientation of the plane of cell expansion. The other involves a change in the hemicellulosic xyloglucan, which inhibits extension growth of these cells. 

---