Cationic Proteins of Human Granulocytes: I. Isolation of the Cationic Proteins from the Granules of Leukaemic Myeloid Cells

Extracts from the granule fraction obtained from leukaemic myeloid cells contained several basic proteins with electrophoretic mobilities against the cathod faster than that for lysozyme. Similar proteins have previously been demonstrated in rabbit polymorphonuclear granules. By chromatography on sulphoethyl Sephadex and on a weak dipolar ion adsorbant the most basic proteins were isolated. The amino acid analysis of the protein gave a preponderance of basic amino acids (29 %) and electrophoresis after treatment with sodium dodecyl sulphate revealed components with the molecular weight in the range 10 , 000–25, 000. These proteins seem to be specific for granulocytes and probably have antibacterial properties.