Andreas,
Running Mascot2XML without any arguments does supply the info you're
looking for:
-E<sample_enzyme>
Recognised <sample_enyzme> (semi-cleavage specification: semi<sample_enyzme>)
trypsin : cut(KR) nocuts(P) sense(C)
Semi-cleavage can be specified as semi<sample_enyzme>,
e.g. semitrypsin, semiargc