Physical properties of two types of calcium stores and SERCAs in human platelets

The aim of this work was to obtain experimental data depending on the properties of calcium stores and SERCAs, to analyse these data in terms of the models based on simulation of the cellular compartments as communicating vessels, and to relate this way the data to the above properties. The main characteristics of the stores and corresponding SERCAs have been estimated. Calcium content in the DTS is similar to 1.5 x 10(6) ions per cell, that in the acidic stores, similar to 0.64 x 10(6) ions per cell. The rate constant of background calcium leakage from the DTS is similar to 0.0033 s(-1), that from the acidic stores, similar to 0.1 s(-1). The background activity of SERCA2b is similar to 0.22 x 10(6) s(-1) ions per cell, that of SERCA3, similar to 2.5 x 10(6) s(-1) ions per cell. The properties of both calcium stores and the SERCAs and the characteristics found might be related to physiological or pathological state of the cells.