Each representative 𝐸𝐸 "⃗ (𝑟𝑟) has geometrically unique features captured through the clustering algorithm, as can be seen upon comparison of the four cluster centers, denoted CYTC-1, CYTC-2, CYTC-3, and CYTC-4, ordered by their frequency of appearance during dynamics (Figure ). All four 𝐸𝐸 "⃗ (𝑟𝑟) conformations for Cyt C have a dominant homogeneous direction toward the same porphyrin nitrogen, but the topology-based clustering method captures subtle differences between them. CYTC-1, which appears in highest frequency, has contributions in the z direction from Fe toward the coordinating His residue, with a small component pointing toward the coordinating Met. CYTC-2 is a rotated field toward the y-axis, and has a weaker field contribution in the -z direction compared to CYTC-1. CYTC-3 is highly similar to CYTC-2, further evidenced by similarities in their magnitude ranges. CYTC-4, the least-visited 𝐸𝐸 "⃗ (𝑟𝑟) conformation, is the most heterogeneous, showing components facing both coordinating ligands, and in both the x and yaxis directions. All these 3-D electric fields have the same characteristic of facing away from the solvent face of the protein where interaction with a Cytochrome C oxidase, for example, would take place -an electric field facing in this direction would favor oxidation of this ferrous form. Our analysis provides a way to capture major and subtle fluctuations in the field geometry, and by taking a perturbative approach of computing the exerted 𝐸𝐸 "⃗ (𝑟𝑟) only from the surrounding environment, removes any sort of bias. To link this quantity to reactivity, we computed oxidation potentials at each representative configuration using QM/MM calculations. The four representative conformations, CYTC-1-4, yielded absolute reduction potentials of 4.79eV, 4.73eV, 5.36eV, and 3.54eV. For comparison, experimental values range from 4.37 to 4.68eV , and an ab initio study by Chen and Hayashi reported a value of 4.34eV . The lowest computed reduction potential was for the least frequent electric field configuration, CYTC-4. The PyCPET method of partitioning molecular dynamics by 𝐸𝐸 "⃗ (𝑟𝑟) configurations reveals the dynamic nature of the reduction potential, which cannot be captured by experimental methods (which are slow and only measure averages), or QM calculations on single structures. Clustering allows us to weight and focus on a few physically informed frames. To ensure that the QM/MM differences in redox potential were not due to merely changes in active site geometry, we obtained QM-region only reduction energies at the QM/MM optimized geometries of 0.94eV, 0.92eV, 0.88eV, and 0.74eV, i.e. in a range near DFT error and not following the same trend as the full QM/MM, confirming this methods ability to capture 𝐸𝐸 "⃗ (𝑟𝑟) configurations with distinct chemical relevance.