Comparison of Alkaline Phosphatase from Human Normal and Leukemic Leukocytes I

The alkaline phosphatase of leukocytes from normal subjects, patients with chronic granulocytic leukemia, and patients with reactive granulocytosis have been characterized by means of agarose column chromatography, sucrose density ultracentrifugation, starch gel electrophoresis, Michaelis constant for p-nitrophenyl phosphate, heat inactivation, inhibition by L-phenylalanine, Ouchterlony double immunodiffusion precipitation, and immunoelectrophoresis using rabbit antileukocyte alkaline phosphatase serum. The same antiserum was used to quantitate the amount of alkaline phosphatase protein in purified preparations of the enzyme obtained from leukocytes of patients with chronic granulocytic leukemia, reactive granulocytosis, and normal individuals. Purified alkaline phosphatase from all three sources had similar biophysical and biochemical characteristics, but the enzyme specific activities were shown to be different using the antiserum and quantitative precipitation technics. This finding was corroborated by using disc gel electrophoresis which showed that similar amounts of enzyme protein had markedly different enzyme activity, i.e., the enzyme from chronic granulocytic leukemic leukocytes had low specific activity, the enzyme from nomal leukocytes had intermediate specific activity, and the enzyme from patients with reactive granulocytosis had a very high specific activity.