SPARQL queries property or class from a schema

Dear all,

suppose we have DATA:

@prefix foaf:  <http://xmlns.com/foaf/0.1/> .

_:a  foaf:name   "Johnny Lee Outlaw" .
_:a  foaf:mbox   <mailto:jlow@example.com> .
_:b  foaf:name   "Peter Goodguy" .
_:b  foaf:mbox   <mailto:peter@example.org> .
_:c  foaf:mbox   <mailto:carol@example.org> .


can we write a SPARQL query like:

PREFIX foaf:   <http://xmlns.com/foaf/0.1/>
SELECT *?property*

WHERE{
             ?x  foaf:*?property*  "Peter Goodguy".
}

if we can not, can we write an equivalent SPARQL query? Namely, can we
decompose schema and Class(or Property) in SPARQL query?

Thanks,
Jitao