Figure 1
From: Proteomic analysis of plasma membrane and secretory vesicles from human neutrophils
Separation of plasma membrane vesicles and secretory vesicles from resting PMN. Isolated resting PMN were disrupted by N2 cavitation and fractionated using a two-step discontinuous gradient of Percoll. The γ-band containing the light membranes was recovered, treated with neuraminidase, and subjected to free-flow electrophoresis to resolve plasma membranes vesicles from secretory vesicles. Fractions (96) were collected and assayed spectrophotometrically for alkaline phosphatase activity in the absence (○) and presence (△) of Triton X-100. Data are expressed as units of absorbance at 405 nm. Latent alkaline phosphatase activity indicates the presence of secretory vesicles.