Tartrate-resistant acid phosphatase of human lung: apparent identity with osteoclastic acid phosphatase

Extracts of human lung tissue contain appreciable activities of a tartrate-resistant acid phosphatase which is apparently identical with the analogous enzyme in bone extracts, with respect to electrophoretic mobility, apparent molecular weight (ca. 37,000), Michaelis constants and relative rates of hydrolysis of various substrates. The acid phosphatase appears to be a constituent of alveolar macrophages. Lung provides a convenient source for the preparation of tartrate-resistant acid phosphatase.