SECRETION OF SUCRASE BY LEISHMANIA-DONOVANI

Leishmania donovani promastigotes were collected, washed, resuspended in buffer, and assayed for sucrase activity. No activity was observed in the intact washed cells, but activity was measurable when the cells were permeabilized with Triton X-100. Intracellular sucrase activity was highest in promastigotes grown at pH 7.4, somewhat lower in promas tigotes grown at pH 5.5, and significantly lower in ''amastigotes'' gr own at pH 5.5. No trehalase, lactase, or maltase activities were obser ved. Assay of the medium in which the cells had grown showed that most the sucrase activity was extracellular, i.e. was secreted into the me dium during growth.