Similarity matrix. Similarity matrix (central figure) of EC 18.104.22.168 (fumarate hydratase). Each point of the 508 × 508 matrix represents the blastp similarity score of two enzymes. All scores above 1500 are reset to 1500. Higher similarity scores yield darker points, (white represents a score below 120). Sequences were sorted by the similarity score, using the longest enzymes as reference to the other enzymes. The three arrows on the right site indicate the positions of enzymes of L. major (red arrows) and H. sapiens (blue arrow). Histograms on the left display the distribution of organisms represented in each cluster, for the three kingdoms: archaebacteria (A), bacteria (B) and eukaryotes (E). In each of the two main (analogous) clusters, subclusters can be observed. The graph at the top of the matrix displays the kingdom of the organism for every enzyme in the matrix.