unable to run commands in shell script after su mqm command,but able to run in putty?Pleae let me know how to execute.?

unable to run commands in shell script after su mqm command,but able to
run in putty?Pleae let me know how to execute.?

My script is,
!/bin/bash
su mqm
echo "DISPLAY QLOCAL () CURDEPTH" | runmqsc QUEUEMANAGER
same command works in putty but not through script.