Localisation of the [32P]IP3 binding site on human platelet intracellular membranes isolated by high‐voltage free‐flow electrophoresis

Publisher Website
Google Scholar
Abstract
This Study reports the localisation of the [32P]IP3 binding site on highly purified membrane fractions prepared using high‐voltage free‐flow electrophoresis. Binding studies on mixed membranes, carried out at 4°C, revealed a binding site with a K d = 86 nM and βmax = 5.3 pmol/mg protein. The binding was potently inhibited by heparin. High‐voltage free‐flow electrophoresis was used to further purify surface and intracellular membranes. The intracellular membranes showed a 5‐fold enrichment of binding sites with respect to the parent mixed membranes with the same K d(80 nM), but the surface membranes showed an absence of binding activity. The results indicate the localisation of the IP3 receptor on highly purified intracellular membranes.