Material Description to be overwritten in PR/PO from material master

Hi,

when we create a PO/PR from ME51n and ME21n the material description field is mandatory hence inspite of making setting as display only in SPRO the inital screen will except any description and will save it.

Is there any thing else by which the description data can be overwritten from material master so that even if the user enters any xyz description the system overwrites it from the material master.

Regards,

Reena