The lysosomal gp63-related protein in Leishmania mexicana amastigotes is a soluble metalloproteinase with an acidic pH optimum.

Leishmania mexicana amastigotes express a lysosomal protein, which is antigenically related to the promastigote surface metalloproteinase (gp63). It is shown that the purified gp63-related protein from amastigote is also an active metalloproteinase. The pH-optimum of the enzyme is acidic, similar to lysosomal cysteine proteinases, but distinct from the neutral to basic pH-optimum of the promastigote surface proteinase. This study appears to be the first report on a metalloproteinase with a lysosomal localization.