Differentiation associated changes in isozyme expression of amino acid naphthylamidase in myeloid cells

Triton X-100 resistant isozymes of amino acid naphthylamidase were studied by polyacrylamide gel electrophoresis, gel filtration and affinity chromatography in samples from 12 human haematopoietic cell lines, 8 leukaemic patients and 4 healthy persons. Affinity to WGA-Sepharose seemed to be correlated to differentiation in the myeloid series, indicating differences in the N-acetyl-glucose-amine content of the enzyme molecules in mature and immature cells. A high carbohydrate content might be characteristic for mature myeloid cells. By trypsin digestion of intact cells and analysis of released enzyme activities into the medium new information on isozyme expression of amino acid naphthylamidase in the granulocyte-monocyte lineages could be achieved.