The DHDPS/NAL subfamily of enzymes share a very similar structure while catalysing a wide variety of reactions in different biochemical pathways. The structural similarity between members allows us to understand how this subfamily of enzymes has evolved. This project characterises some of the more obscure enzymes in the DHDPS/NAL subfamily in order to investigate evolutionary relationships within this subfamily of proteins. This will be done though techniques to investigate the structural states of these proteins as well as their solution based structure. There are three protein groups under investigation: trans-hydroxybenzylidenepyruvate hydratase-aldolase (tHBP-HA), 1-pyrroline-4-hydroxy-2-carboxylate deaminase (HypD) and eukaryotic n-acetylneuraminate lyase (NAL). THBP-HA catalyses the final step of the naphthalene degradation pathway, HypD is involved in Hydroxyproline metabolism and NAL is involved in Sialic acid metabolism. Analytical ultracentrifugation (AUC) has been used to probe the oligomeric states of the proteins to confirm if they are similar to the tetrameric DHDPS/NAL. Small angle x-ray scattering has been used to confirm if the solution structures are constant with the AUC in solution. Structure for tHBP-HA from P.fluorescens was solved through X-ray crystallography to 2.2Â, allowing for investigation of the active site.