The efficiency of GDH and AAT encapsulation into erythrocytes and comparison of experimental results and model calculations for systems containing these enzymes. (a) The relative inclusion efficiency (R) and the yield of encapsulation (E) are presented for each enzyme. Additionally, the yield of the cells (C) is shown. The GDH and AAT concentrations in the initial suspension of RBCs during loading were 10 IU/mlsuspension and 5 IU/mlsuspension, respectively. All the parameters were normally distributed. The mean values ± SEM (n = 10) are presented. (b) Comparison of the theoretically calculated and in vitro measured rate of ammonium utilization by a mixture of GDH and AAT directly added to a buffer containing 0.5 mM ammonium. The final activities of GDH and AAT in the mixture were 0.3 IU/ml and 1.5 IU/ml, respectively. The mean values ± SD are shown (n = 4). (c) The experimental and theoretically calculated rates of ammonium consumption by EBRs containing GDH and AAT. The final enzyme activities were 0.10 and 0.28 IU/mlsuspension, respectively (the haematocrit of the suspension averaged 9.3%). As a control the RBCs without included enzymes were used (n = 4). The mean values ± SD are shown (n = 3). (d) Comparison of the calculated and experimentally measured stationary rate of ammonium consumption (in a medium without erythrocytes) at the different ratios of AAT and GDH activities. The values for the mean ± SD are presented (n = 4). The conditions for measuring and the concentrations of the metabolites for modelling are described in the Methods section and shown in Tables 1 and 2.