Kyle,
if the stored procedures are in the database the database level permission EXECUTE should do the trick.
DENY EXECUTE TO PUBLIC
In case it has permissions to execute any stored procedures that start with sp_ and are in the master database (these are accessible in all databases), you will need to deny permission to these in the master database as well.
Regards,
Andras
Andras Belokosztolszki, MCPD, PhD
GoldenGate Software