This study examines the effects of various protoporphyrinogen oxidase mutations responsible for variegate porphyria, the role of the arginine-59 residue, and the glycines in the conserved flavin binding site, in catalysis and/or cofactor binding. Wild type recombinant human protoporphyrinogen oxidase and a selection of both naturally occurring and self-designed mutants were generated, expresses and purified. The self designed mutants included a conservative and two non-conservative arginine-59 replacements, and substitution of glycine residues at positions 9, 11, and 14 by alanine. The expression and purification for all protoporphyrinogen oxidases was optimised, enabling their purification to homogeneity by single step metal affinity chromatography.

Bibliography: p. 131-170.