MVK class I are inhibited by metabolites downstream of the diphosphomevalonate carboxylase reaction (IPP, DMAPP, GPP, FPP and longer chain isoprenoids), MVK class II are inhibited by diphosphomevalonate (DPM), but not by metabolites downstream of diphosphomevalonate carboxylase, and MVK class III are not inhibited by isoprenoids [18 ].
Source: wiktionary