Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences

First Advisor

Cotter, D.


Biology, Microbiology.



Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


The cysteine proteinases of Dictyostelium discoideum are unique enzymes in that they are found to be reversibly activated by pH shuffles in their lysosomal/endosomal microenvironments. Previous work has hypothesised that proteinases were present in the extracellular matrix (ECM) of the pseudoplasmodium of D. discoideum. This work shows that acid-activatable cysteine proteinases are secreted during the aggregation of myxamoebae and the migration of the pseudoplasmodium. When assayed by gelatin-SDS-PAGE during the course of multicellular development in D. discoideum, the intracellular level of proteinases was found to decrease as development proceeded. However, this work finds that there is an increase in external levels of cysteine proteinases as multicellular development proceeds. The disulfide bonding of D. discoideum spore proteinases ddCP43 and ddCP48 were characterized and were observed to lack interdisulfide bonds. Native-PAGE analysis reveals two separate bands when the same sample were analyzed. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1998 .G35. Source: Masters Abstracts International, Volume: 39-02, page: 0448. Adviser: D. A. Cotter. Thesis (M.Sc.)--University of Windsor (Canada), 1998.