Purification of the 47 kDa phosphoprotein associated with the NADPH oxidase of human neutrophils

A 47 kDa protein in the cytosol of phagocytic cells becomes heavily phosphorylated and translocates to the cell membrane upon stimulation. This protein was isolated from the cytosol of human neutrophils by chromatography on ion-exchange and hydroxyapatite resins. Polyclonal antibodies to this protein demonstrated that it was present in the neutrophils of two patients with X-linked chronic granulomatous disease (CGD) but not in those of three patients with the autosomal recessive pattern of inheritance. A sequence of amino acids was determined from a tryptic peptide of this protein: Glu-Met-Phe-Pro-Ile-Glu-Ala-Gly-Ala-Ile-Asn-Xaa-Glu. This served to establish that the phosphoprotein isolated here is the same as a protein of a similar molecular mass identified by other workers. These studies confirm the involvement of this 47 kDa phosphoprotein in the molecular pathology of autosomal recessive CGD and describe a method for the purification of the native protein.