Carboxypeptidase that catalyzes the release of a C-terminal amino acid, but has little or no action with -Asp, -Glu, -Arg, -Lys or -Pro (PubMed:20385563, PubMed:8806703). Catalyzes the conversion of leukotriene C4 to leukotriene F4 via the hydrolysis of an amide bond (By similarity).