Metacaspases are proteases that participate in proteolytic and autoproteolytic activity to regulate cellular processes, namely apoptosis. This project focuses on Type I metacaspases of the fungus Schizophyllum commune (ScMCA-Ia). These metacaspases are thought to bind calcium to be considered active. To investigate the unknown structural characteristics and the calcium binding sites of these proteins, previous work has used differential scanning fluorimetry (DSF). This method takes advantage of protein denaturation at increasing temperatures and our lab has investigated ScMCA-Ia calcium binding using this technique. However, some of the mutant proteins are evidently too unstable at high temperatures and so calcium binding data cannot reliably be obtained for these mutants. To avoid this issue, we use spectroscopic techniques. In circular dichroism spectroscopy (CD) a sample is struck with circularly polarized light and can be used to detect interactions between the incident light and key protein structural elements. Alpha helices and beta strands are the two most prominent secondary protein structures and they each interact with this circularly polarized light at unique wavelengths. Currently, CD spectra for samples of purified protein with gradually increasing concentrations of calcium are obtained and the change in signal corresponds to conformational changes in the protein structure as it binds calcium. Fitting the experimental data to one-site specific binding and two-site specific binding curves provides information about the calcium binding site(s) in ScMCA-Ia. In work that has been completed so far, the data obtained by CD is consistent with the wildtype data obtained using DSF. That is, the wild type protein appears to have two calcium binding sites, as evidenced by both DSF and CD methods. Additionally, a mutant of the proposed high affinity calcium binding site, that was previously unable to be analyzed by DSF, now appears to fit a one-site specific binding model for calcium, which supports the wild type two-site calcium binding model. Future work will focus on repetition and replication of the wild type calcium titration data. Additionally, future experiments will use data processing of the proposed high and low affinity calcium binding site mutant titrations to further investigate the wild type two-site calcium binding hypothesis.