Hydroxyproline: Observations on its chemical and autoradiographical localization in plant cell wall protein.

In sycamore suspension cells both autoradiographical and chemical techniques have confirmed the idea that most of the protein that contains hydroxyproline is located within the cell wall. Relatively more hydroxyproline is incorporated into the walls of stationary phase cells than into those of cells actively engaged in cell division. It is probable that the protein enters the wall during and after the later stages of cell plate consolidation, and this may be facilitated by means of smooth membrane. Distinctive and heavy incorporation of radioactive proline is found associated with unusual wall thickenings or 'warts'.