New Subunit in L-Phenylalanine Oxidase from Pseudomonas sp. P-501 and the Primary Structure

L-phenylalanine oxidase from Pseudomonas sp. P-501 was shown by isoelectric focusing and HPLC experiments to consist of two kinds of nonidentical subunits. The newly identified subunit is designated as α, and the larger subunit, which has been reported previously, as β. The apparent molecular weight of α subunit was estimated to be 8200 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. From the molecular mass of each subunits and their contents in the enzyme, the enzyme was shown to be composed of two α and two β subunits. The amino acid sequence analysis of α subunit showed that the subunit consists of 92 amino acid residues and contains considerably hydrophobic arrangements and the candidate for the common sequence characteristic of the AMP binding in the FAD binding domain.