Purification, N-terminal amino acid sequence and properties of hydroxymethylbilane synthase (porphobilinogen deaminase) from Escherichia coli

Abstract

Hydroxymethylbilane synthase (porphobilinogen deaminase) was purified to apparent homogeneity from Escherichia coli. The enzyme is a monomer of M(r) approx. 40,000. The K(m) for porphobilinogen and relative V(max) values have been obtained at various pH values over the range 6.2-8.8, enabling pK values for ionizable groups important for activity to be determined. The N-terminal amino acid sequence is presented.