Electrophoretic Separation of Multiple Forms of Particle Associated Acid Phosphatase.

A considerable body of evidence supports the contention that much, if not all, cellular acid phosphatase is contained within particles designated as IYSOsomes (deDuve, 1959; Novikoff, 1961). Release of the enzyme from these particles is effected by conditions that destroy the integrity of the lysosomal membrane. Often a discrepancy is found between the total activity of acid phosphatase and the activity of released, unsedimentable, enzyme. This discrepancy is assumed to be due to retention of soluble enzyme within collapsed lysosomal vesicles and to the secondary adsorption of enzyme to cellular structure. This could be explained alternately by the existence, within the lysosomal particle, of two categories of acid phosphatase : one present in readily releasable “soluble” form and the other present in a more firmly “bound” form. This alternate hypothesis is suggested by experiments of Barka ( 196 1 b ) , which showed the release of a chromatographically distinct acid phosphatase following the treatment of rat liver homogenates with Triton X-100. This paper deals with the electrophoretic demonstration of multiple acid phosphatases associated with particles and their differential release.