Analysis of Leishmania proteinases reveals developmental changes in species‐specific forms and a common 68‐kDa activity

The proteinases of three species of Leishmania have been analysed by electrophoresis. Amastigotes of L. mexicana mexicana have several high‐activity, low‐Mr cysteine proteinases which are absent from log‐phase promastigotes of L. m. mexicana and from all developmental stages of the other species analysed (L. donovani and L. major). Low‐activity, low‐Mr proteinases were present in populations of stationary‐phase promastigotes of L. m. mexicana. All three species of Leishmania had higher Mr proteinases, a number of which showed developmental regulation, some of them being stage‐specific. Significantly, at all stages of the life cycle in all three species a 68‐kDa proteinase was apparent. In its size, sensitivity to inhibitors and ability to bind concanavalin A‐agarose, this resembles the major surface protein thought to be present in all Leishmania species and which has recently been reported to possess proteinase activity in L. major promastigotes.