paehowun57:/home/insgipdm/sqllib> db2 describe table syscat.routineauth
Column Type Type
name schema name Length Scale Nulls
------------------------------ --------- ------------------ -------- ----- ------
GRANTOR SYSIBM VARCHAR 128 0 No
GRANTEE SYSIBM VARCHAR 128 0 No
GRANTEETYPE SYSIBM CHARACTER 1 0 No
SCHEMA SYSIBM VARCHAR 128 0 No
SPECIFICNAME SYSIBM VARCHAR 128 0 Yes
TYPESCHEMA SYSIBM VARCHAR 128 0 Yes
TYPENAME SYSIBM VARCHAR 128 0 Yes
ROUTINETYPE SYSIBM CHARACTER 1 0 No
EXECUTEAUTH SYSIBM CHARACTER 1 0 No
GRANT_TIME SYSIBM TIMESTAMP 10 0 No
So, you could issue a select against syscat.routineauth with grantee.