Abstract
The intracellular localization of alkaline phosphatase has been determined in human neutrophils with analytical subcellular fractionation by density gradient centrifugation and EM cytochemistry. Centrifugation on sucrose gradients containing 1 mM EDTA and 5 units/ml of heparin showed that alkaline phosphatase was associated with a membranous component distinct from plasma membrane, mitochondria, specific granules and azurophil granules. There was no resolution from the endoplasmic reticulum. Density gradient centrifugation on a sucrose-imidazole-heparin gradient showed a clear resolution of the alkaline phosphatase-containing membranes from the Golgi and endoplasmic reticulum. Density gradient centrifugation of neutrophils that had been disrupted in the presence of 0.12 mmol/l digitonin clearly separated alkaline phosphatase-containing membranes from the endoplasmic reticulum. Part of the γ-glutamyl transferase has a similar localization to that of alkaline phosphatase. EM cytochemistry of neutrophils, neutrophil homogenates and of the density gradient fractions identified alkaline phosphatase-containing granules as irregular-shaped, often tubular, structures. It is suggested that alkaline phosphatase and part of the γ-glutamyl transferase activity are localized to a unique organelle in the human neutrophil.
| Original language | English |
|---|---|
| Pages (from-to) | 401-412 |
| Number of pages | 12 |
| Journal | Journal of Cell Science |
| Volume | VOL 36 |
| State | Published - 1979 |
| Externally published | Yes |